A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.
ENDOPEPTIDASES which have a cysteine involved in the catalytic process. This group of enzymes is inactivated by CYSTEINE PROTEINASE INHIBITORS such as CYSTATINS and SULFHYDRYL REAGENTS.
A subclass of peptide hydrolases that depend on a CYSTEINE residue for their activity.
An enzyme that catalyzes the conversion of L-CYSTEINE to 3-sulfinoalanine (3-sulfino-L-alanine) in the CYSTEINE metabolism and TAURINE and hypotaurine metabolic pathways.
Exogenous and endogenous compounds which inhibit CYSTEINE ENDOPEPTIDASES.
An enzyme that catalyzes the biosynthesis of cysteine in microorganisms and plants from O-acetyl-L-serine and hydrogen sulfide. This enzyme was formerly listed as EC 4.2.99.8.
The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.
Chemical groups containing the covalent disulfide bonds -S-S-. The sulfur atoms can be bound to inorganic or organic moieties.
Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.
Compounds containing the -SH radical.
A covalently linked dimeric nonessential amino acid formed by the oxidation of CYSTEINE. Two molecules of cysteine are joined together by a disulfide bridge to form cystine.
Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.
A group of lysosomal proteinases or endopeptidases found in aqueous extracts of a variety of animal tissues. They function optimally within an acidic pH range. The cathepsins occur as a variety of enzyme subtypes including SERINE PROTEASES; ASPARTIC PROTEINASES; and CYSTEINE PROTEASES.
A homologous group of endogenous CYSTEINE PROTEINASE INHIBITORS. The cystatins inhibit most CYSTEINE ENDOPEPTIDASES such as PAPAIN, and other peptidases which have a sulfhydryl group at the active site.
A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).
A ubiquitously-expressed cysteine protease that plays an enzymatic role in POST-TRANSLATIONAL PROTEIN PROCESSING of proteins within SECRETORY GRANULES.
A proteolytic enzyme obtained from Carica papaya. It is also the name used for a purified mixture of papain and CHYMOPAPAIN that is used as a topical enzymatic debriding agent. EC 3.4.22.2.
The parts of a macromolecule that directly participate in its specific combination with another molecule.
A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.
Chemical agents that react with SH groups. This is a chemically diverse group that is used for a variety of purposes. Among these are enzyme inhibition, enzyme reactivation or protection, and labelling.
A lysosomal cysteine proteinase with a specificity similar to that of PAPAIN. The enzyme is present in a variety of tissues and is important in many physiological and pathological processes. In pathology, cathepsin B has been found to be involved in DEMYELINATION; EMPHYSEMA; RHEUMATOID ARTHRITIS, and NEOPLASM INVASIVENESS.
The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.
Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.
The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.
Proteins prepared by recombinant DNA technology.
The rate dynamics in chemical or physical systems.
Enzymes that catalyze the cleavage of a carbon-sulfur bond by means other than hydrolysis or oxidation. EC 4.4.
The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).
Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.
A sulfhydryl reagent that is widely used in experimental biochemical studies.
A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.
An enzyme that catalyzes the conversion of L-SERINE to COENZYME A and O-acetyl-L-serine, using ACETYL-COA as a donor.
The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.
An element that is a member of the chalcogen family. It has an atomic symbol S, atomic number 16, and atomic weight [32.059; 32.076]. It is found in the amino acids cysteine and methionine.
A reagent commonly used in biochemical studies as a protective agent to prevent the oxidation of SH (thiol) groups and for reducing disulphides to dithiols.
Organic salts or esters of methanesulfonic acid.
A standard reagent for the determination of reactive sulfhydryl groups by absorbance measurements. It is used primarily for the determination of sulfhydryl and disulfide groups in proteins. The color produced is due to the formation of a thio anion, 3-carboxyl-4-nitrothiophenolate.
The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.
The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.
The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
An alkylating sulfhydryl reagent. Its actions are similar to those of iodoacetate.
The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.
Materials that add an electron to an element or compound, that is, decrease the positiveness of its valence. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)
The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.
Any of the monobasic inorganic or organic acids of sulfur with the general formula RSO(OH). (From McGraw Hill Dictionary of Scientific and Technical Terms, 4th ed)
A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.
A sulfur-containing essential L-amino acid that is important in many body functions.
A derivative of ACETIC ACID that contains one IODINE atom attached to its methyl group.
Organic compounds that generally contain an amino (-NH2) and a carboxyl (-COOH) group. Twenty alpha-amino acids are the subunits which are polymerized to form proteins.
A multifunctional pyridoxal phosphate enzyme. In the final step in the biosynthesis of cysteine it catalyzes the cleavage of cystathionine to yield cysteine, ammonia, and 2-ketobutyrate. EC 4.4.1.1.
A class of enzymes that catalyze the cleavage of C-C, C-O, and C-N, and other bonds by other means than by hydrolysis or oxidation. (Enzyme Nomenclature, 1992) EC 4.
The level of protein structure in which regular hydrogen-bond interactions within contiguous stretches of polypeptide chain give rise to alpha helices, beta strands (which align to form beta sheets) or other types of coils. This is the first folding level of protein conformation.
Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.
A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.
The covalent bonding of an alkyl group to an organic compound. It can occur by a simple addition reaction or by substitution of another functional group.
Hydrogen-donating proteins that participates in a variety of biochemical reactions including ribonucleotide reduction and reduction of PEROXIREDOXINS. Thioredoxin is oxidized from a dithiol to a disulfide when acting as a reducing cofactor. The disulfide form is then reduced by NADPH in a reaction catalyzed by THIOREDOXIN REDUCTASE.
Oxy acids of sulfur with the general formula RSOH, where R is an alkyl or aryl group such as CH3. They are often encountered as esters and halides. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.
'Sulfur-containing amino acids' are a category of amino acids, the building blocks of proteins, that include methionine and cysteine, which contain sulfur atoms as part of their side chains, playing crucial roles in protein structure, enzyme function, and antioxidant defense.
Proteins found in any species of bacterium.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Any of various enzymatically catalyzed post-translational modifications of PEPTIDES or PROTEINS in the cell of origin. These modifications include carboxylation; HYDROXYLATION; ACETYLATION; PHOSPHORYLATION; METHYLATION; GLYCOSYLATION; ubiquitination; oxidation; proteolysis; and crosslinking and result in changes in molecular weight and electrophoretic motility.
The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.
Established cell cultures that have the potential to propagate indefinitely.
A cytotoxic sulfhydryl reagent that inhibits several subcellular metabolic systems and is used as a tool in cellular physiology.
The N-acetyl derivative of CYSTEINE. It is used as a mucolytic agent to reduce the viscosity of mucous secretions. It has also been shown to have antiviral effects in patients with HIV due to inhibition of viral stimulation by reactive oxygen intermediates.
Non-collagenous, calcium-binding glycoprotein of developing bone. It links collagen to mineral in the bone matrix. In the synonym SPARC glycoprotein, the acronym stands for Secreted Protein, Acidic and Rich in Cysteine.
Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.
Covalent attachment of LIPIDS and FATTY ACIDS to other compounds and PROTEINS.
A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.
One of the enzymes active in the gamma-glutamyl cycle. It catalyzes the synthesis of gamma-glutamylcysteine from glutamate and cysteine in the presence of ATP with the formation of ADP and orthophosphate. EC 6.3.2.2.
Oxidoreductases with specificity for oxidation or reduction of SULFUR COMPOUNDS.
Compounds which inhibit or antagonize biosynthesis or actions of proteases (ENDOPEPTIDASES).
An antineoplastic agent with alkylating properties. It also acts as a mutagen by damaging DNA and is used experimentally for that effect.
Iodinated derivatives of acetic acid. Iodoacetates are commonly used as alkylating sulfhydryl reagents and enzyme inhibitors in biochemical research.
A conditionally essential nutrient, important during mammalian development. It is present in milk but is isolated mostly from ox bile and strongly conjugates bile acids.
An intracellular cystatin subtype that is found in a broad variety of cell types. It is a cytosolic enzyme inhibitor that protects the cell against the proteolytic action of lysosomal enzymes such as CATHEPSINS.
Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.
Peptides composed of two amino acid units.
An essential amino acid that is required for the production of HISTAMINE.
An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.
Chemical groups containing the covalent sulfur bonds -S-. The sulfur atom can be bound to inorganic or organic moieties.
A cysteine protease that is highly expressed in OSTEOCLASTS and plays an essential role in BONE RESORPTION as a potent EXTRACELLULAR MATRIX-degrading enzyme.
The process by which two molecules of the same chemical composition form a condensation product or polymer.
A metallic element of atomic number 30 and atomic weight 65.38. It is a necessary trace element in the diet, forming an essential part of many enzymes, and playing an important role in protein synthesis and in cell division. Zinc deficiency is associated with ANEMIA, short stature, HYPOGONADISM, impaired WOUND HEALING, and geophagia. It is known by the symbol Zn.
A group of proteins possessing only the iron-sulfur complex as the prosthetic group. These proteins participate in all major pathways of electron transport: photosynthesis, respiration, hydroxylation and bacterial hydrogen and nitrogen fixation.
Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.
A family of ubiquitously-expressed peroxidases that play a role in the reduction of a broad spectrum of PEROXIDES like HYDROGEN PEROXIDE; LIPID PEROXIDES and peroxinitrite. They are found in a wide range of organisms, such as BACTERIA; PLANTS; and MAMMALS. The enzyme requires the presence of a thiol-containing intermediate such as THIOREDOXIN as a reducing cofactor.
Single-stranded complementary DNA synthesized from an RNA template by the action of RNA-dependent DNA polymerase. cDNA (i.e., complementary DNA, not circular DNA, not C-DNA) is used in a variety of molecular cloning experiments as well as serving as a specific hybridization probe.
Cystathionine is an intermediate sulfur-containing amino acid in the transsulfuration pathway, formed from homocysteine and serine by the enzyme cystathionine beta-synthase, which is involved in the biosynthesis of cysteine and glutathione.
Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.
The sum of the weight of all the atoms in a molecule.
A non-essential amino acid that occurs in high levels in its free state in plasma. It is produced from pyruvate by transamination. It is involved in sugar and acid metabolism, increases IMMUNITY, and provides energy for muscle tissue, BRAIN, and the CENTRAL NERVOUS SYSTEM.
The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Reagents with two reactive groups, usually at opposite ends of the molecule, that are capable of reacting with and thereby forming bridges between side chains of amino acids in proteins; the locations of naturally reactive areas within proteins can thereby be identified; may also be used for other macromolecules, like glycoproteins, nucleic acids, or other.
A cytastin subtype found at high levels in the SKIN and in BLOOD CELLS. Cystatin A incorporates into the cornified cell envelope of stratified squamous epithelial cells and may play a role in bacteriostatic properties of skin.
Short sequences (generally about 10 base pairs) of DNA that are complementary to sequences of messenger RNA and allow reverse transcriptases to start copying the adjacent sequences of mRNA. Primers are used extensively in genetic and molecular biology techniques.
A serine endopeptidase that is formed from TRYPSINOGEN in the pancreas. It is converted into its active form by ENTEROPEPTIDASE in the small intestine. It catalyzes hydrolysis of the carboxyl group of either arginine or lysine. EC 3.4.21.4.
Proteins which are found in membranes including cellular and intracellular membranes. They consist of two types, peripheral and integral proteins. They include most membrane-associated enzymes, antigenic proteins, transport proteins, and drug, hormone, and lectin receptors.
Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.
Linear POLYPEPTIDES that are synthesized on RIBOSOMES and may be further modified, crosslinked, cleaved, or assembled into complex proteins with several subunits. The specific sequence of AMINO ACIDS determines the shape the polypeptide will take, during PROTEIN FOLDING, and the function of the protein.
The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)
The process of cleaving a chemical compound by the addition of a molecule of water.
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
Cysteine proteinase found in many tissues. Hydrolyzes a variety of endogenous proteins including NEUROPEPTIDES; CYTOSKELETAL PROTEINS; proteins from SMOOTH MUSCLE; CARDIAC MUSCLE; liver; platelets; and erythrocytes. Two subclasses having high and low calcium sensitivity are known. Removes Z-discs and M-lines from myofibrils. Activates phosphorylase kinase and cyclic nucleotide-independent protein kinase. This enzyme was formerly listed as EC 3.4.22.4.
Substances used for the detection, identification, analysis, etc. of chemical, biological, or pathologic processes or conditions. Indicators are substances that change in physical appearance, e.g., color, at or approaching the endpoint of a chemical titration, e.g., on the passage between acidity and alkalinity. Reagents are substances used for the detection or determination of another substance by chemical or microscopical means, especially analysis. Types of reagents are precipitants, solvents, oxidizers, reducers, fluxes, and colorimetric reagents. (From Grant & Hackh's Chemical Dictionary, 5th ed, p301, p499)
A non-essential amino acid. It is found primarily in gelatin and silk fibroin and used therapeutically as a nutrient. It is also a fast inhibitory neurotransmitter.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
A lysosomal papain-related cysteine proteinase that is expressed in a broad variety of cell types.
A family of thioltransferases that contain two active site CYSTEINE residues, which either form a disulfide (oxidized form) or a dithiol (reduced form). They function as an electron carrier in the GLUTHIONE-dependent synthesis of deoxyribonucleotides by RIBONUCLEOTIDE REDUCTASES and may play a role in the deglutathionylation of protein thiols. The oxidized forms of glutaredoxins are directly reduced by the GLUTATHIONE.
Analysis of PEPTIDES that are generated from the digestion or fragmentation of a protein or mixture of PROTEINS, by ELECTROPHORESIS; CHROMATOGRAPHY; or MASS SPECTROMETRY. The resulting peptide fingerprints are analyzed for a variety of purposes including the identification of the proteins in a sample, GENETIC POLYMORPHISMS, patterns of gene expression, and patterns diagnostic for diseases.
A sulfhydryl proteinase with cysteine at the active site from ficus latex. Preferential cleavage is at tyrosine and phenylalanine residues. EC 3.4.22.3.
The uptake of naked or purified DNA by CELLS, usually meaning the process as it occurs in eukaryotic cells. It is analogous to bacterial transformation (TRANSFORMATION, BACTERIAL) and both are routinely employed in GENE TRANSFER TECHNIQUES.
A common saturated fatty acid found in fats and waxes including olive oil, palm oil, and body lipids.
A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.
Phenanthrolines are a class of heterocyclic compounds containing two aromatic hydrocarbon rings fused with a third ring consisting of nitrogen atoms, which have been used in the development of various pharmaceutical and chemical research applications, including as antibacterial, antifungal, and antiviral agents, enzyme inhibitors, and chelators.
Maleimides are a class of chemically reactive compounds containing a maleimide functional group, which can undergo addition reactions with nucleophiles such as thiols, making them useful for the formation of covalent bonds in various bioconjugation and material synthesis applications.
Enzymes which transfer sulfur atoms to various acceptor molecules. EC 2.8.1.
A multifunctional pyridoxal phosphate enzyme. In the second stage of cysteine biosynthesis it catalyzes the reaction of homocysteine with serine to form cystathionine with the elimination of water. Deficiency of this enzyme leads to HYPERHOMOCYSTEINEMIA and HOMOCYSTINURIA. EC 4.2.1.22.
Inorganic salts of sulfuric acid.
Diazomethane is an extremely hazardous and unstable organic compound, (CH2)N=N=O, with a methane substituted diazo group, that is highly explosive when heated, shocked or contaminated, and used as a powerful methylating agent in chemical syntheses, but its production and handling require special expertise and equipment due to the high risks involved.
Conversion of an inactive form of an enzyme to one possessing metabolic activity. It includes 1, activation by ions (activators); 2, activation by cofactors (coenzymes); and 3, conversion of an enzyme precursor (proenzyme or zymogen) to an active enzyme.
A cyclized derivative of L-GLUTAMIC ACID. Elevated blood levels may be associated with problems of GLUTAMINE or GLUTATHIONE metabolism.
A change from planar to elliptic polarization when an initially plane-polarized light wave traverses an optically active medium. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
A mercaptoethylamine compound that is endogenously derived from the COENZYME A degradative pathway. The fact that cysteamine is readily transported into LYSOSOMES where it reacts with CYSTINE to form cysteine-cysteamine disulfide and CYSTEINE has led to its use in CYSTINE DEPLETING AGENTS for the treatment of CYSTINOSIS.
Proteins obtained from ESCHERICHIA COLI.
A mutation caused by the substitution of one nucleotide for another. This results in the DNA molecule having a change in a single base pair.
An essential branched-chain amino acid important for hemoglobin formation.
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
A sulfur-containing alkyl thionitrite that is one of the NITRIC OXIDE DONORS.
The location of the atoms, groups or ions relative to one another in a molecule, as well as the number, type and location of covalent bonds.
Theoretical representations that simulate the behavior or activity of chemical processes or phenomena; includes the use of mathematical equations, computers, and other electronic equipment.
A GLUTATHIONE dimer formed by a disulfide bond between the cysteine sulfhydryl side chains during the course of being oxidized.
Conversion into nitroso compounds. An example is the reaction of nitrites with amino compounds to form carcinogenic N-nitrosamines.
A mass spectrometric technique that is used for the analysis of large biomolecules. Analyte molecules are embedded in an excess matrix of small organic molecules that show a high resonant absorption at the laser wavelength used. The matrix absorbs the laser energy, thus inducing a soft disintegration of the sample-matrix mixture into free (gas phase) matrix and analyte molecules and molecular ions. In general, only molecular ions of the analyte molecules are produced, and almost no fragmentation occurs. This makes the method well suited for molecular weight determinations and mixture analysis.
A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).
Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.
Transport proteins that carry specific substances in the blood or across cell membranes.
Inorganic or organic compounds that contain sulfur as an integral part of the molecule.
The addition of an organic acid radical into a molecule.
The extent to which an enzyme retains its structural conformation or its activity when subjected to storage, isolation, and purification or various other physical or chemical manipulations, including proteolytic enzymes and heat.
An element with atomic symbol Cd, atomic number 48, and atomic weight 114. It is a metal and ingestion will lead to CADMIUM POISONING.
Enzymes that catalyze the cleavage of a carbon-oxygen bond by means other than hydrolysis or oxidation. EC 4.2.
Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.
Procedures by which protein structure and function are changed or created in vitro by altering existing or synthesizing new structural genes that direct the synthesis of proteins with sought-after properties. Such procedures may include the design of MOLECULAR MODELS of proteins using COMPUTER GRAPHICS or other molecular modeling techniques; site-specific mutagenesis (MUTAGENESIS, SITE-SPECIFIC) of existing genes; and DIRECTED MOLECULAR EVOLUTION techniques to create new genes.
A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.
CELL LINES derived from the CV-1 cell line by transformation with a replication origin defective mutant of SV40 VIRUS, which codes for wild type large T antigen (ANTIGENS, POLYOMAVIRUS TRANSFORMING). They are used for transfection and cloning. (The CV-1 cell line was derived from the kidney of an adult male African green monkey (CERCOPITHECUS AETHIOPS).)

An antiviral mechanism of nitric oxide: inhibition of a viral protease. (1/10540)

Although nitric oxide (NO) kills or inhibits the replication of a variety of intracellular pathogens, the antimicrobial mechanisms of NO are unknown. Here, we identify a viral protease as a target of NO. The life cycle of many viruses depends upon viral proteases that cleave viral polyproteins into individual polypeptides. NO inactivates the Coxsackievirus protease 3C, an enzyme necessary for the replication of Coxsackievirus. NO S-nitrosylates the cysteine residue in the active site of protease 3C, inhibiting protease activity and interrupting the viral life cycle. Substituting a serine residue for the active site cysteine renders protease 3C resistant to NO inhibition. Since cysteine proteases are critical for virulence or replication of many viruses, bacteria, and parasites, S-nitrosylation of pathogen cysteine proteases may be a general mechanism of antimicrobial host defenses.  (+info)

Cloning of the peroxiredoxin gene family in rats and characterization of the fourth member. (2/10540)

Peroxiredoxin (PRx) exhibits thioredoxin-dependent peroxidase activity and constitutes a family of proteins. Four members of genes from rat tissues were isolated by PCR using degenerated primers based on the sequences which encode a pair of highly conserved Cys-containing domains, and were then cloned to full-length cDNAs. These included two genes which have previously been isolated in rats, PRx I and PRx II, and two rat homologues of PRx III and PRx IV. We showed, for the first time, the simultaneous expression of all four genes in various rat tissues by Northern blotting. Since a discrepancy exists regarding cellular distribution, we further characterized PRx IV by expressing it in COS-1 cells. This clearly demonstrates that PRx IV is a secretory form and functions within the extracellular space.  (+info)

Kinetics of oxidation of aliphatic and aromatic thiols by myeloperoxidase compounds I and II. (3/10540)

Myeloperoxidase (MPO) is the most abundant protein in neutrophils and plays a central role in microbial killing and inflammatory tissue damage. Because most of the non-steroidal anti-inflammatory drugs and other drugs contain a thiol group, it is necessary to understand how these substrates are oxidized by MPO. We have performed transient kinetic measurements to study the oxidation of 14 aliphatic and aromatic mono- and dithiols by the MPO intermediates, Compound I (k3) and Compound II (k4), using sequential mixing stopped-flow techniques. The one-electron reduction of Compound I by aromatic thiols (e.g. methimidazole, 2-mercaptopurine and 6-mercaptopurine) varied by less than a factor of seven (between 1.39 +/- 0.12 x 10(5) M(-1) s(-1) and 9.16 +/- 1.63 x 10(5) M(-1) s(-1)), whereas reduction by aliphatic thiols was demonstrated to depend on their overall net charge and hydrophobic character and not on the percentage of thiol deprotonation or redox potential. Cysteamine, cysteine methyl ester, cysteine ethyl ester and alpha-lipoic acid showed k3 values comparable to aromatic thiols, whereas a free carboxy group (e.g. cysteine, N-acetylcysteine, glutathione) diminished k3 dramatically. The one-electron reduction of Compound II was far more constrained by the nature of the substrate. Reduction by methimidazole, 2-mercaptopurine and 6-mercaptopurine showed second-order rate constants (k4) of 1.33 +/- 0.08 x 10(5) M(-1) s(-1), 5.25 +/- 0.07 x 10(5) M(-1) s(-1) and 3.03 +/- 0.07 x 10(3) M(-1) s(-1). Even at high concentrations cysteine, penicillamine and glutathione could not reduce Compound II, whereas cysteamine (4.27 +/- 0.05 x 10(3) M(-1) s(-1)), cysteine methyl ester (8.14 +/- 0.08 x 10(3) M(-1) s(-1)), cysteine ethyl ester (3.76 +/- 0.17 x 10(3) M(-1) s(-1)) and alpha-lipoic acid (4.78 +/- 0.07 x 10(4) M(-1) s(-1)) were demonstrated to reduce Compound II and thus could be expected to be oxidized by MPO without co-substrates.  (+info)

Internal electron transfer between hemes and Cu(II) bound at cysteine beta93 promotes methemoglobin reduction by carbon monoxide. (4/10540)

Previous studies showed that CO/H2O oxidation provides electrons to drive the reduction of oxidized hemoglobin (metHb). We report here that Cu(II) addition accelerates the rate of metHb beta chain reduction by CO by a factor of about 1000. A mechanism whereby electron transfer occurs via an internal pathway coupling CO/H2O oxidation to Fe(III) and Cu(II) reduction is suggested by the observation that the copper-induced rate enhancement is inhibited by blocking Cys-beta93 with N-ethylmaleimide. Furthermore, this internal electron-transfer pathway is more readily established at low Cu(II) concentrations in Hb Deer Lodge (beta2His --> Arg) and other species lacking His-beta2 than in Hb A0. This difference is consistent with preferential binding of Cu(II) in Hb A0 to a high affinity site involving His-beta2, which is ineffective in promoting electron exchange between Cu(II) and the beta heme iron. Effective electron transfer is thus affected by Hb type but is not governed by the R left arrow over right arrow T conformational equilibrium. The beta hemes in Cu(II)-metHb are reduced under CO at rates close to those observed for cytochrome c oxidase, where heme and copper are present together in the oxygen-binding site and where internal electron transfer also occurs.  (+info)

Plasma total homocysteine and cysteine in relation to glomerular filtration rate in diabetes mellitus. (5/10540)

BACKGROUND: The plasma concentrations of total homocysteine (tHcy) and total cysteine (tCys) are determined by intracellular metabolism and by renal plasma clearance, and we hypothesized that glomerular filtration is a major determinant of plasma tHcy and tCys. We studied the relationships between the glomerular filtration rate (GFR) and plasma tHcy and tCys in populations of diabetic patients with particularly wide ranges of GFR. METHODS: We measured GFR, urine albumin excretion rate (UAER), plasma tHcy, tCys, methionine, vitamin B12, folate, C-peptide, and routine parameters in 50 insulin-dependent diabetes mellitus (IDDM) and 30 non-insulin-dependent diabetes mellitus (NIDDM) patients. All patients underwent intensive insulin treatment and had a serum creatinine concentration below 115 micromol/liter. RESULTS: Mean plasma tHcy in diabetic patients (0.1 micromol/liter) was lower than in normal persons (11.1 micromol/liter, P = 0.0014). Mean plasma tCys in diabetic patients (266.1 micromol/liter) was also lower than in normal persons (281.9 micromol/liter, P = 0.0005). Seventy-three percent of the diabetic patients had relative hyperfiltration. Plasma tHcy and tCys were closely and independently associated with GFR, serum folate, and serum B12. However, plasma tHcy was not independently associated with any of the 22 other variables tested, including age, serum creatinine concentration, UAER, total daily insulin dose, and glycemic control. CONCLUSIONS: Glomerular filtration rate is an independent determinant of plasma tHcy and tCys concentrations, and GFR is rate limiting for renal clearance of both homocysteine and cysteine in diabetic patients without overt nephropathy. Declining GFR explains the age-related increase in plasma tHcy, and hyperfiltration explains the lower than normal mean plasma tHcy and tCys concentrations in populations of diabetic patients.  (+info)

Variants of ribonuclease inhibitor that resist oxidation. (6/10540)

Human ribonuclease inhibitor (hRI) is a cytosolic protein that protects cells from the adventitious invasion of pancreatic-type ribonucleases. hRI has 32 cysteine residues. The oxidation of these cysteine residues to form disulfide bonds is a rapid, cooperative process that inactivates hRI. The most proximal cysteine residues in native hRI are two pairs that are adjacent in sequence: Cys94 and Cys95, and Cys328 and Cys329. A cystine formed from such adjacent cysteine residues would likely contain a perturbing cis peptide bond within its eight-membered ring, which would disrupt the structure of hRI and could facilitate further oxidation. We find that replacing Cys328 and Cys329 with alanine residues has little effect on the affinity of hRI for bovine pancreatic ribonuclease A (RNase A), but increases its resistance to oxidation by 10- to 15-fold. Similar effects are observed for the single variants, C328A hRI and C329A hRI, suggesting that oxidation resistance arises from the inability to form a Cys328-Cys329 disulfide bond. Replacing Cys94 and Cys95 with alanine residues increases oxidation resistance to a lesser extent, and decreases the affinity of hRI for RNase A. The C328A, C329A, and C328A/C329A variants are likely to be more useful than wild-type hRI for inhibiting pancreatic-type ribonucleases in vitro and in vivo. We conclude that replacing adjacent cysteine residues can confer oxidation resistance in a protein.  (+info)

Metal-catalyzed oxidation of phenylalanine-sensitive 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase from Escherichia coli: inactivation and destabilization by oxidation of active-site cysteines. (7/10540)

The in vitro instability of the phenylalanine-sensitive 3-deoxy-D-arabino-heptulosonate-7-phosphate synthase [DAHPS(Phe)] from Escherichia coli has been found to be due to a metal-catalyzed oxidation mechanism. DAHPS(Phe) is one of three differentially feedback-regulated isoforms of the enzyme which catalyzes the first step of aromatic biosynthesis, the formation of DAHP from phosphoenolpyruvate and D-erythrose-4-phosphate. The activity of the apoenzyme decayed exponentially, with a half-life of about 1 day at room temperature, and the heterotetramer slowly dissociated to the monomeric state. The enzyme was stabilized by the presence of phosphoenolpyruvate or EDTA, indicating that in the absence of substrate, a trace metal(s) was the inactivating agent. Cu2+ and Fe2+, but none of the other divalent metals that activate the enzyme, greatly accelerated the rate of inactivation and subunit dissociation. Both anaerobiosis and the addition of catalase significantly reduced Cu2+-catalyzed inactivation. In the spontaneously inactivated enzyme, there was a net loss of two of the seven thiols per subunit; this value increased with increasing concentrations of added Cu2+. Dithiothreitol completely restored the enzymatic activity and the two lost thiols in the spontaneously inactivated enzyme but was only partially effective in reactivation of the Cu2+-inactivated enzyme. Mutant enzymes with conservative replacements at either of the two active-site cysteines, Cys61 or Cys328, were insensitive to the metal attack. Peptide mapping of the Cu2+-inactivated enzyme revealed a disulfide linkage between these two cysteine residues. All results indicate that DAHPS(Phe) is a metal-catalyzed oxidation system wherein bound substrate protects active-site residues from oxidative attack catalyzed by bound redox metal cofactor. A mechanism of inactivation of DAHPS is proposed that features a metal redox cycle that requires the sequential oxidation of its two active-site cysteines.  (+info)

Functional importance and local environments of the cysteines in the tetracycline resistance protein encoded by plasmid pBR322. (8/10540)

The properties of the cysteines in the pBR322-encoded tetracycline resistance protein have been examined. Cysteines are important but not essential for tetracycline transport activity. None of the cysteines reacted with biotin maleimide, suggesting that they are shielded from the aqueous phase or reside in a negatively charged local environment.  (+info)

Cysteine is a semi-essential amino acid, which means that it can be produced by the human body under normal circumstances, but may need to be obtained from external sources in certain conditions such as illness or stress. Its chemical formula is HO2CCH(NH2)CH2SH, and it contains a sulfhydryl group (-SH), which allows it to act as a powerful antioxidant and participate in various cellular processes.

Cysteine plays important roles in protein structure and function, detoxification, and the synthesis of other molecules such as glutathione, taurine, and coenzyme A. It is also involved in wound healing, immune response, and the maintenance of healthy skin, hair, and nails.

Cysteine can be found in a variety of foods, including meat, poultry, fish, dairy products, eggs, legumes, nuts, seeds, and some grains. It is also available as a dietary supplement and can be used in the treatment of various medical conditions such as liver disease, bronchitis, and heavy metal toxicity. However, excessive intake of cysteine may have adverse effects on health, including gastrointestinal disturbances, nausea, vomiting, and headaches.

Cysteine endopeptidases are a type of enzymes that cleave peptide bonds within proteins. They are also known as cysteine proteases or cysteine proteinases. These enzymes contain a catalytic triad consisting of three amino acids: cysteine, histidine, and aspartate. The thiol group (-SH) of the cysteine residue acts as a nucleophile and attacks the carbonyl carbon of the peptide bond, leading to its cleavage.

Cysteine endopeptidases play important roles in various biological processes, including protein degradation, cell signaling, and inflammation. They are involved in many physiological and pathological conditions, such as apoptosis, immune response, and cancer. Some examples of cysteine endopeptidases include cathepsins, caspases, and calpains.

It is important to note that these enzymes require a reducing environment to maintain the reduced state of their active site cysteine residue. Therefore, they are sensitive to oxidizing agents and inhibitors that target the thiol group. Understanding the structure and function of cysteine endopeptidases is crucial for developing therapeutic strategies that target these enzymes in various diseases.

Cysteine proteases are a type of enzymes that cleave peptide bonds in proteins, and they require a cysteine residue in their active site to do so. These enzymes play important roles in various biological processes, including protein degradation, cell signaling, and inflammation. They can be found in various tissues and organisms, including humans, where they are involved in many physiological and pathological conditions.

Cysteine proteases are characterized by a conserved catalytic mechanism that involves a nucleophilic attack on the peptide bond carbonyl carbon by the thiolate anion of the cysteine residue, resulting in the formation of an acyl-enzyme intermediate. This intermediate is then hydrolyzed to release the cleaved protein fragments.

Some examples of cysteine proteases include cathepsins, caspases, and calpains, which are involved in various cellular processes such as apoptosis, autophagy, and signal transduction. Dysregulation of these enzymes has been implicated in several diseases, including cancer, neurodegenerative disorders, and infectious diseases. Therefore, cysteine proteases have emerged as important therapeutic targets for the development of new drugs to treat these conditions.

Cysteine dioxygenase (CDO) is an enzyme that catalyzes the conversion of the amino acid L-cysteine to L-cysteinesulfinic acid, which is the first step in the catabolism of L-cysteine. This reaction also generates molecular oxygen as a byproduct. CDO plays important roles in various biological processes such as neurotransmitter biosynthesis and oxidative stress response. It exists as two isoforms, CDO1 and CDO2, which are encoded by separate genes and have distinct tissue distributions and functions.

Cysteine proteinase inhibitors are a type of molecule that bind to and inhibit the activity of cysteine proteases, which are enzymes that cleave proteins at specific sites containing the amino acid cysteine. These inhibitors play important roles in regulating various biological processes, including inflammation, immune response, and programmed cell death (apoptosis). They can also have potential therapeutic applications in diseases where excessive protease activity contributes to pathology, such as cancer, arthritis, and neurodegenerative disorders. Examples of cysteine proteinase inhibitors include cystatins, kininogens, and serpins.

Cysteine synthase is an enzyme involved in the biosynthesis of the amino acid cysteine. It catalyzes the reaction that combines O-acetylserine and hydrogen sulfide to produce cysteine and acetic acid. This enzyme plays a crucial role in maintaining the sulfur balance in cells, as cysteine is a sulfur-containing amino acid that is an important component of proteins and many other molecules in the body. There are two forms of cysteine synthase: one that is found in bacteria and plants, and another that is found in animals. The animal form of the enzyme is also known as cystathionine beta-synthase, and it has a broader specificity than the bacterial and plant forms, as it can also catalyze the reaction that produces cystathionine from serine and homocysteine.

An amino acid sequence is the specific order of amino acids in a protein or peptide molecule, formed by the linking of the amino group (-NH2) of one amino acid to the carboxyl group (-COOH) of another amino acid through a peptide bond. The sequence is determined by the genetic code and is unique to each type of protein or peptide. It plays a crucial role in determining the three-dimensional structure and function of proteins.

Disulfides are a type of organic compound that contains a sulfur-sulfur bond. In the context of biochemistry and medicine, disulfide bonds are often found in proteins, where they play a crucial role in maintaining their three-dimensional structure and function. These bonds form when two sulfhydryl groups (-SH) on cysteine residues within a protein molecule react with each other, releasing a molecule of water and creating a disulfide bond (-S-S-) between the two cysteines. Disulfide bonds can be reduced back to sulfhydryl groups by various reducing agents, which is an important process in many biological reactions. The formation and reduction of disulfide bonds are critical for the proper folding, stability, and activity of many proteins, including those involved in various physiological processes and diseases.

Molecular sequence data refers to the specific arrangement of molecules, most commonly nucleotides in DNA or RNA, or amino acids in proteins, that make up a biological macromolecule. This data is generated through laboratory techniques such as sequencing, and provides information about the exact order of the constituent molecules. This data is crucial in various fields of biology, including genetics, evolution, and molecular biology, allowing for comparisons between different organisms, identification of genetic variations, and studies of gene function and regulation.

Sulfhydryl compounds, also known as thiol compounds, are organic compounds that contain a functional group consisting of a sulfur atom bonded to a hydrogen atom (-SH). This functional group is also called a sulfhydryl group. Sulfhydryl compounds can be found in various biological systems and play important roles in maintaining the structure and function of proteins, enzymes, and other biomolecules. They can also act as antioxidants and help protect cells from damage caused by reactive oxygen species. Examples of sulfhydryl compounds include cysteine, glutathione, and coenzyme A.

Cystine is a naturally occurring amino acid in the body, which is formed from the oxidation of two cysteine molecules. It is a non-essential amino acid, meaning that it can be produced by the body and does not need to be obtained through diet. Cystine plays important roles in various biological processes, including protein structure and antioxidant defense. However, when cystine accumulates in large amounts, it can form crystals or stones, leading to conditions such as cystinuria, a genetic disorder characterized by the formation of cystine kidney stones.

Site-directed mutagenesis is a molecular biology technique used to introduce specific and targeted changes to a specific DNA sequence. This process involves creating a new variant of a gene or a specific region of interest within a DNA molecule by introducing a planned, deliberate change, or mutation, at a predetermined site within the DNA sequence.

The methodology typically involves the use of molecular tools such as PCR (polymerase chain reaction), restriction enzymes, and/or ligases to introduce the desired mutation(s) into a plasmid or other vector containing the target DNA sequence. The resulting modified DNA molecule can then be used to transform host cells, allowing for the production of large quantities of the mutated gene or protein for further study.

Site-directed mutagenesis is a valuable tool in basic research, drug discovery, and biotechnology applications where specific changes to a DNA sequence are required to understand gene function, investigate protein structure/function relationships, or engineer novel biological properties into existing genes or proteins.

Cathepsins are a type of proteolytic enzymes, which are found in lysosomes and are responsible for breaking down proteins inside the cell. They are classified as papain-like cysteine proteases and play important roles in various physiological processes, including tissue remodeling, antigen presentation, and apoptosis (programmed cell death). There are several different types of cathepsins, including cathepsin B, C, D, F, H, K, L, S, V, and X/Z, each with distinct substrate specificities and functions.

Dysregulation of cathepsins has been implicated in various pathological conditions, such as cancer, neurodegenerative diseases, and inflammatory disorders. For example, overexpression or hyperactivation of certain cathepsins has been shown to contribute to tumor invasion and metastasis, while their inhibition has been explored as a potential therapeutic strategy in cancer treatment. Similarly, abnormal levels of cathepsins have been linked to the progression of neurodegenerative diseases like Alzheimer's and Parkinson's, making them attractive targets for drug development.

Cystatins are a group of proteins that inhibit cysteine proteases, which are enzymes that break down other proteins. Cystatins are found in various biological fluids and tissues, including tears, saliva, seminal plasma, and urine. They play an important role in regulating protein catabolism and protecting cells from excessive protease activity. There are three main types of cystatins: type 1 (cystatin C), type 2 (cystatin M, cystatin N, and fetuin), and type 3 (kininogens). Abnormal levels of cystatins have been associated with various pathological conditions, such as cancer, neurodegenerative diseases, and inflammatory disorders.

Oxidation-Reduction (redox) reactions are a type of chemical reaction involving a transfer of electrons between two species. The substance that loses electrons in the reaction is oxidized, and the substance that gains electrons is reduced. Oxidation and reduction always occur together in a redox reaction, hence the term "oxidation-reduction."

In biological systems, redox reactions play a crucial role in many cellular processes, including energy production, metabolism, and signaling. The transfer of electrons in these reactions is often facilitated by specialized molecules called electron carriers, such as nicotinamide adenine dinucleotide (NAD+/NADH) and flavin adenine dinucleotide (FAD/FADH2).

The oxidation state of an element in a compound is a measure of the number of electrons that have been gained or lost relative to its neutral state. In redox reactions, the oxidation state of one or more elements changes as they gain or lose electrons. The substance that is oxidized has a higher oxidation state, while the substance that is reduced has a lower oxidation state.

Overall, oxidation-reduction reactions are fundamental to the functioning of living organisms and are involved in many important biological processes.

Cathepsin L is a lysosomal cysteine protease that plays a role in various physiological processes, including protein degradation, antigen presentation, and extracellular matrix remodeling. It is produced as an inactive precursor and activated by cleavage of its propeptide domain. Cathepsin L has a broad specificity for peptide bonds and can cleave both intracellular and extracellular proteins, making it an important player in various pathological conditions such as cancer, neurodegenerative diseases, and infectious diseases. Inhibition of cathepsin L has been explored as a potential therapeutic strategy for these conditions.

Papain is defined as a proteolytic enzyme that is derived from the latex of the papaya tree (Carica papaya). It has the ability to break down other proteins into smaller peptides or individual amino acids. Papain is widely used in various industries, including the food industry for tenderizing meat and brewing beer, as well as in the medical field for its digestive and anti-inflammatory properties.

In medicine, papain is sometimes used topically to help heal burns, wounds, and skin ulcers. It can also be taken orally to treat indigestion, parasitic infections, and other gastrointestinal disorders. However, its use as a medical treatment is not widely accepted and more research is needed to establish its safety and efficacy.

In the context of medical and biological sciences, a "binding site" refers to a specific location on a protein, molecule, or cell where another molecule can attach or bind. This binding interaction can lead to various functional changes in the original protein or molecule. The other molecule that binds to the binding site is often referred to as a ligand, which can be a small molecule, ion, or even another protein.

The binding between a ligand and its target binding site can be specific and selective, meaning that only certain ligands can bind to particular binding sites with high affinity. This specificity plays a crucial role in various biological processes, such as signal transduction, enzyme catalysis, or drug action.

In the case of drug development, understanding the location and properties of binding sites on target proteins is essential for designing drugs that can selectively bind to these sites and modulate protein function. This knowledge can help create more effective and safer therapeutic options for various diseases.

Glutathione is a tripeptide composed of three amino acids: cysteine, glutamic acid, and glycine. It is a vital antioxidant that plays an essential role in maintaining cellular health and function. Glutathione helps protect cells from oxidative stress by neutralizing free radicals, which are unstable molecules that can damage cells and contribute to aging and diseases such as cancer, heart disease, and dementia. It also supports the immune system, detoxifies harmful substances, and regulates various cellular processes, including DNA synthesis and repair.

Glutathione is found in every cell of the body, with particularly high concentrations in the liver, lungs, and eyes. The body can produce its own glutathione, but levels may decline with age, illness, or exposure to toxins. As such, maintaining optimal glutathione levels through diet, supplementation, or other means is essential for overall health and well-being.

Sulfhydryl reagents are chemical compounds that react with sulfhydryl groups (-SH), which are found in certain amino acids such as cysteine. These reagents can be used to modify or inhibit the function of proteins by forming disulfide bonds or adding functional groups to the sulfur atom. Examples of sulfhydryl reagents include N-ethylmaleimide (NEM), p-chloromercuribenzoate (PCMB), and iodoacetamide. These reagents are widely used in biochemistry and molecular biology research to study protein structure and function, as well as in the development of drugs and therapeutic agents.

Cathepsin B is a lysosomal cysteine protease that plays a role in various physiological processes, including intracellular protein degradation, antigen presentation, and extracellular matrix remodeling. It is produced as an inactive precursor (procathepsin B) and activated upon cleavage of the propeptide by other proteases or autocatalytically. Cathepsin B has a wide range of substrates, including collagen, elastin, and various intracellular proteins. Its dysregulation has been implicated in several pathological conditions, such as cancer, neurodegenerative diseases, and inflammatory disorders.

Sequence homology, amino acid, refers to the similarity in the order of amino acids in a protein or a portion of a protein between two or more species. This similarity can be used to infer evolutionary relationships and functional similarities between proteins. The higher the degree of sequence homology, the more likely it is that the proteins are related and have similar functions. Sequence homology can be determined through various methods such as pairwise alignment or multiple sequence alignment, which compare the sequences and calculate a score based on the number and type of matching amino acids.

Molecular models are three-dimensional representations of molecular structures that are used in the field of molecular biology and chemistry to visualize and understand the spatial arrangement of atoms and bonds within a molecule. These models can be physical or computer-generated and allow researchers to study the shape, size, and behavior of molecules, which is crucial for understanding their function and interactions with other molecules.

Physical molecular models are often made up of balls (representing atoms) connected by rods or sticks (representing bonds). These models can be constructed manually using materials such as plastic or wooden balls and rods, or they can be created using 3D printing technology.

Computer-generated molecular models, on the other hand, are created using specialized software that allows researchers to visualize and manipulate molecular structures in three dimensions. These models can be used to simulate molecular interactions, predict molecular behavior, and design new drugs or chemicals with specific properties. Overall, molecular models play a critical role in advancing our understanding of molecular structures and their functions.

A base sequence in the context of molecular biology refers to the specific order of nucleotides in a DNA or RNA molecule. In DNA, these nucleotides are adenine (A), guanine (G), cytosine (C), and thymine (T). In RNA, uracil (U) takes the place of thymine. The base sequence contains genetic information that is transcribed into RNA and ultimately translated into proteins. It is the exact order of these bases that determines the genetic code and thus the function of the DNA or RNA molecule.

Recombinant proteins are artificially created proteins produced through the use of recombinant DNA technology. This process involves combining DNA molecules from different sources to create a new set of genes that encode for a specific protein. The resulting recombinant protein can then be expressed, purified, and used for various applications in research, medicine, and industry.

Recombinant proteins are widely used in biomedical research to study protein function, structure, and interactions. They are also used in the development of diagnostic tests, vaccines, and therapeutic drugs. For example, recombinant insulin is a common treatment for diabetes, while recombinant human growth hormone is used to treat growth disorders.

The production of recombinant proteins typically involves the use of host cells, such as bacteria, yeast, or mammalian cells, which are engineered to express the desired protein. The host cells are transformed with a plasmid vector containing the gene of interest, along with regulatory elements that control its expression. Once the host cells are cultured and the protein is expressed, it can be purified using various chromatography techniques.

Overall, recombinant proteins have revolutionized many areas of biology and medicine, enabling researchers to study and manipulate proteins in ways that were previously impossible.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Carbon-sulfur lyases are a class of enzymes that catalyze the cleavage of carbon-sulfur bonds in organic compounds, resulting in the formation of a new double bond. These enzymes play important roles in various biological processes, including the metabolism of sulfur-containing amino acids and the biosynthesis of certain cofactors and secondary metabolites.

Carbon-sulfur lyases are classified under EC number 4.4.1, which includes enzymes that catalyze the formation of carbon-carbon bonds by means other than those involving oxidoreductases. Within this class, carbon-sulfur lyases are further divided into several subcategories based on their specific reaction mechanisms and substrate specificities.

One example of a carbon-sulfur lyase is cysteine desulfurase (EC 2.8.1.7), which catalyzes the formation of alanine and a persulfide group from L-cysteine, releasing elemental sulfur as a byproduct. This enzyme plays a critical role in the biosynthesis of iron-sulfur clusters, which are essential cofactors for many proteins involved in electron transfer reactions.

Another example is 3-mercaptopyruvate sulfurtransferase (EC 2.8.1.2), which catalyzes the formation of a persulfide group on a cysteine residue in the enzyme itself, using 3-mercaptopyruvate as a sulfur donor. This enzyme is involved in the biosynthesis of various secondary metabolites containing sulfur atoms, such as allicin in garlic and penicillamine in certain fungi.

Overall, carbon-sulfur lyases are important enzymes that play critical roles in various biological processes involving the cleavage or formation of carbon-sulfur bonds.

Protein conformation refers to the specific three-dimensional shape that a protein molecule assumes due to the spatial arrangement of its constituent amino acid residues and their associated chemical groups. This complex structure is determined by several factors, including covalent bonds (disulfide bridges), hydrogen bonds, van der Waals forces, and ionic bonds, which help stabilize the protein's unique conformation.

Protein conformations can be broadly classified into two categories: primary, secondary, tertiary, and quaternary structures. The primary structure represents the linear sequence of amino acids in a polypeptide chain. The secondary structure arises from local interactions between adjacent amino acid residues, leading to the formation of recurring motifs such as Ī±-helices and Ī²-sheets. Tertiary structure refers to the overall three-dimensional folding pattern of a single polypeptide chain, while quaternary structure describes the spatial arrangement of multiple folded polypeptide chains (subunits) that interact to form a functional protein complex.

Understanding protein conformation is crucial for elucidating protein function, as the specific three-dimensional shape of a protein directly influences its ability to interact with other molecules, such as ligands, nucleic acids, or other proteins. Any alterations in protein conformation due to genetic mutations, environmental factors, or chemical modifications can lead to loss of function, misfolding, aggregation, and disease states like neurodegenerative disorders and cancer.

A mutation is a permanent change in the DNA sequence of an organism's genome. Mutations can occur spontaneously or be caused by environmental factors such as exposure to radiation, chemicals, or viruses. They may have various effects on the organism, ranging from benign to harmful, depending on where they occur and whether they alter the function of essential proteins. In some cases, mutations can increase an individual's susceptibility to certain diseases or disorders, while in others, they may confer a survival advantage. Mutations are the driving force behind evolution, as they introduce new genetic variability into populations, which can then be acted upon by natural selection.

Ethylmaleimide is a chemical compound that is commonly used in research and scientific studies. Its chemical formula is C7H10N2S. It is known to modify proteins by forming covalent bonds with them, which can alter their function or structure. This property makes it a useful tool in the study of protein function and interactions.

In a medical context, Ethylmaleimide is not used as a therapeutic agent due to its reactivity and potential toxicity. However, it has been used in research to investigate various physiological processes, including the regulation of ion channels and the modulation of enzyme activity. It is important to note that the use of Ethylmaleimide in medical research should be carried out with appropriate precautions and safety measures due to its potential hazards.

'Escherichia coli' (E. coli) is a type of gram-negative, facultatively anaerobic, rod-shaped bacterium that commonly inhabits the intestinal tract of humans and warm-blooded animals. It is a member of the family Enterobacteriaceae and one of the most well-studied prokaryotic model organisms in molecular biology.

While most E. coli strains are harmless and even beneficial to their hosts, some serotypes can cause various forms of gastrointestinal and extraintestinal illnesses in humans and animals. These pathogenic strains possess virulence factors that enable them to colonize and damage host tissues, leading to diseases such as diarrhea, urinary tract infections, pneumonia, and sepsis.

E. coli is a versatile organism with remarkable genetic diversity, which allows it to adapt to various environmental niches. It can be found in water, soil, food, and various man-made environments, making it an essential indicator of fecal contamination and a common cause of foodborne illnesses. The study of E. coli has contributed significantly to our understanding of fundamental biological processes, including DNA replication, gene regulation, and protein synthesis.

Serine O-acetyltransferase (SAT) is an enzyme involved in the biosynthesis of cysteine, an amino acid that is a crucial component of proteins. This enzyme catalyzes the transfer of an acetyl group from acetyl-CoA to the amino acid serine, forming O-acetylserine and CoA. The O-acetylserine is then converted into cysteine through a series of additional reactions. SAT plays a critical role in maintaining the balance of sulfur-containing amino acids in cells and has been implicated in various cellular processes, including stress response, antioxidant defense, and protein folding. Dysregulation of SAT activity has been associated with several diseases, such as cancer, neurodegenerative disorders, and cardiovascular disease.

Tertiary protein structure refers to the three-dimensional arrangement of all the elements (polypeptide chains) of a single protein molecule. It is the highest level of structural organization and results from interactions between various side chains (R groups) of the amino acids that make up the protein. These interactions, which include hydrogen bonds, ionic bonds, van der Waals forces, and disulfide bridges, give the protein its unique shape and stability, which in turn determines its function. The tertiary structure of a protein can be stabilized by various factors such as temperature, pH, and the presence of certain ions. Any changes in these factors can lead to denaturation, where the protein loses its tertiary structure and thus its function.

Sulfur is not typically referred to in the context of a medical definition, as it is an element found in nature and not a specific medical condition or concept. However, sulfur does have some relevance to certain medical topics:

* Sulfur is an essential element that is a component of several amino acids (the building blocks of proteins) and is necessary for the proper functioning of enzymes and other biological processes in the body.
* Sulfur-containing compounds, such as glutathione, play important roles in antioxidant defense and detoxification in the body.
* Some medications and supplements contain sulfur or sulfur-containing compounds, such as dimethyl sulfoxide (DMSO), which is used topically for pain relief and inflammation.
* Sulfur baths and other forms of sulfur-based therapies have been used historically in alternative medicine to treat various conditions, although their effectiveness is not well-established by scientific research.

It's important to note that while sulfur itself is not a medical term, it can be relevant to certain medical topics and should be discussed with a healthcare professional if you have any questions or concerns about its use in medications, supplements, or therapies.

Dithiothreitol (DTT) is a reducing agent, which is a type of chemical compound that breaks disulfide bonds between cysteine residues in proteins. DTT is commonly used in biochemistry and molecular biology research to prevent the formation of disulfide bonds during protein purification and manipulation.

Chemically, DTT is a small molecule with two sulfhydryl groups (-SH) that can donate electrons to oxidized cysteine residues in proteins, converting them to their reduced form (-S-H). This reaction reduces disulfide bonds and helps to maintain the solubility and stability of proteins.

DTT is also used as an antioxidant to prevent the oxidation of other molecules, such as DNA and enzymes, during experimental procedures. However, it should be noted that DTT can also reduce other types of bonds, including those in metal ions and certain chemical dyes, so its use must be carefully controlled and monitored.

A mesylate is a salt formed when mesylic acid (methanesulfonic acid) reacts with a base. In the context of pharmaceuticals, many drugs are available in mesylate form as it can be more soluble and bioavailable than other forms. Mesylates are commonly used to improve the absorption and effectiveness of medications.

For example, a drug called atenolol (a beta blocker used to treat high blood pressure) is often formulated as atenolol mesylate because the mesylate form is more soluble in water than the free base form, making it easier for the body to absorb and utilize the medication.

It's important to note that mesylates are not a specific medical condition or disease, but rather a type of pharmaceutical preparation.

Dithionitrobenzoic acid is not a medical term, as it is related to chemistry rather than medicine. It is an organic compound with the formula C6H4N2O4S2. This compound is a type of benzenediol that contains two sulfur atoms and two nitro groups. It is a white crystalline powder that is soluble in water and alcohol.

Dithionitrobenzoic acid is not used directly in medical applications, but it can be used as a reagent in chemical reactions that are relevant to medical research or analysis. For example, it can be used to determine the concentration of iron in biological samples through a reaction that produces a colored complex. However, if you have any specific questions related to its use or application in a medical context, I would recommend consulting with a medical professional or a researcher in the relevant field.

An amino acid substitution is a type of mutation in which one amino acid in a protein is replaced by another. This occurs when there is a change in the DNA sequence that codes for a particular amino acid in a protein. The genetic code is redundant, meaning that most amino acids are encoded by more than one codon (a sequence of three nucleotides). As a result, a single base pair change in the DNA sequence may not necessarily lead to an amino acid substitution. However, if a change does occur, it can have a variety of effects on the protein's structure and function, depending on the nature of the substituted amino acids. Some substitutions may be harmless, while others may alter the protein's activity or stability, leading to disease.

Molecular cloning is a laboratory technique used to create multiple copies of a specific DNA sequence. This process involves several steps:

1. Isolation: The first step in molecular cloning is to isolate the DNA sequence of interest from the rest of the genomic DNA. This can be done using various methods such as PCR (polymerase chain reaction), restriction enzymes, or hybridization.
2. Vector construction: Once the DNA sequence of interest has been isolated, it must be inserted into a vector, which is a small circular DNA molecule that can replicate independently in a host cell. Common vectors used in molecular cloning include plasmids and phages.
3. Transformation: The constructed vector is then introduced into a host cell, usually a bacterial or yeast cell, through a process called transformation. This can be done using various methods such as electroporation or chemical transformation.
4. Selection: After transformation, the host cells are grown in selective media that allow only those cells containing the vector to grow. This ensures that the DNA sequence of interest has been successfully cloned into the vector.
5. Amplification: Once the host cells have been selected, they can be grown in large quantities to amplify the number of copies of the cloned DNA sequence.

Molecular cloning is a powerful tool in molecular biology and has numerous applications, including the production of recombinant proteins, gene therapy, functional analysis of genes, and genetic engineering.

Protein binding, in the context of medical and biological sciences, refers to the interaction between a protein and another molecule (known as the ligand) that results in a stable complex. This process is often reversible and can be influenced by various factors such as pH, temperature, and concentration of the involved molecules.

In clinical chemistry, protein binding is particularly important when it comes to drugs, as many of them bind to proteins (especially albumin) in the bloodstream. The degree of protein binding can affect a drug's distribution, metabolism, and excretion, which in turn influence its therapeutic effectiveness and potential side effects.

Protein-bound drugs may be less available for interaction with their target tissues, as only the unbound or "free" fraction of the drug is active. Therefore, understanding protein binding can help optimize dosing regimens and minimize adverse reactions.

Iodoacetamide is not typically defined in a medical context, but it is a chemical compound with the formula CH3C(=NH)COI. It is used in laboratory settings as a reagent for various chemical reactions. In a biochemical context, iodoacetamide is an alkylating agent that can react with cysteine residues in proteins, modifying their structure and function. This property has made it useful in research applications such as the study of protein function and enzyme kinetics.

However, it's important to note that iodoacetamide is not used as a therapeutic agent in medicine due to its potential toxicity and reactivity with various biological molecules. Therefore, there is no medical definition for this compound.

A Structure-Activity Relationship (SAR) in the context of medicinal chemistry and pharmacology refers to the relationship between the chemical structure of a drug or molecule and its biological activity or effect on a target protein, cell, or organism. SAR studies aim to identify patterns and correlations between structural features of a compound and its ability to interact with a specific biological target, leading to a desired therapeutic response or undesired side effects.

By analyzing the SAR, researchers can optimize the chemical structure of lead compounds to enhance their potency, selectivity, safety, and pharmacokinetic properties, ultimately guiding the design and development of novel drugs with improved efficacy and reduced toxicity.

A reducing agent, in the context of biochemistry and medicine, is a substance that donates electrons to another molecule, thereby reducing it. This process is known as reduction, which is the opposite of oxidation. Reducing agents are often used in chemical reactions to reduce the oxidation state of other compounds. In medical terms, reducing agents may be used in various treatments and therapies, such as wound healing and antioxidant defense systems, where they help protect cells from damage caused by free radicals and other reactive oxygen species. Examples of reducing agents include ascorbic acid (vitamin C), glutathione, and certain enzymes like NADPH-dependent reductases.

In genetics, sequence alignment is the process of arranging two or more DNA, RNA, or protein sequences to identify regions of similarity or homology between them. This is often done using computational methods to compare the nucleotide or amino acid sequences and identify matching patterns, which can provide insight into evolutionary relationships, functional domains, or potential genetic disorders. The alignment process typically involves adjusting gaps and mismatches in the sequences to maximize the similarity between them, resulting in an aligned sequence that can be visually represented and analyzed.

I apologize for any confusion, but "Sulfinic Acids" is not a term used in medical definitions. It is a term from the field of chemistry. Sulfinic acids are organic compounds that contain a functional group with the formula RSO(O)H, where R represents an alkyl or aryl group. They are important intermediates in organic synthesis and can be found in some natural sources. If you have any questions related to medical terminology or concepts, I would be happy to help!

Substrate specificity in the context of medical biochemistry and enzymology refers to the ability of an enzyme to selectively bind and catalyze a chemical reaction with a particular substrate (or a group of similar substrates) while discriminating against other molecules that are not substrates. This specificity arises from the three-dimensional structure of the enzyme, which has evolved to match the shape, charge distribution, and functional groups of its physiological substrate(s).

Substrate specificity is a fundamental property of enzymes that enables them to carry out highly selective chemical transformations in the complex cellular environment. The active site of an enzyme, where the catalysis takes place, has a unique conformation that complements the shape and charge distribution of its substrate(s). This ensures efficient recognition, binding, and conversion of the substrate into the desired product while minimizing unwanted side reactions with other molecules.

Substrate specificity can be categorized as:

1. Absolute specificity: An enzyme that can only act on a single substrate or a very narrow group of structurally related substrates, showing no activity towards any other molecule.
2. Group specificity: An enzyme that prefers to act on a particular functional group or class of compounds but can still accommodate minor structural variations within the substrate.
3. Broad or promiscuous specificity: An enzyme that can act on a wide range of structurally diverse substrates, albeit with varying catalytic efficiencies.

Understanding substrate specificity is crucial for elucidating enzymatic mechanisms, designing drugs that target specific enzymes or pathways, and developing biotechnological applications that rely on the controlled manipulation of enzyme activities.

Methionine is an essential amino acid, which means that it cannot be synthesized by the human body and must be obtained through the diet. It plays a crucial role in various biological processes, including:

1. Protein synthesis: Methionine is one of the building blocks of proteins, helping to create new proteins and maintain the structure and function of cells.
2. Methylation: Methionine serves as a methyl group donor in various biochemical reactions, which are essential for DNA synthesis, gene regulation, and neurotransmitter production.
3. Antioxidant defense: Methionine can be converted to cysteine, which is involved in the formation of glutathione, a potent antioxidant that helps protect cells from oxidative damage.
4. Homocysteine metabolism: Methionine is involved in the conversion of homocysteine back to methionine through a process called remethylation, which is essential for maintaining normal homocysteine levels and preventing cardiovascular disease.
5. Fat metabolism: Methionine helps facilitate the breakdown and metabolism of fats in the body.

Foods rich in methionine include meat, fish, dairy products, eggs, and some nuts and seeds.

Iodoacetic acid is not typically defined in the context of medical terminology, but rather it is a chemical compound with the formula CH2ICO2H. It is a colorless, oily liquid that is used in organic synthesis as an alkylating agent and also has been studied for its potential antibacterial and antifungal properties.

In medical contexts, iodoacetic acid may be mentioned in relation to its use in research or in the discussion of certain chemical reactions that may occur in the body. For example, it can inhibit the enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH), which plays a crucial role in energy metabolism. However, iodoacetic acid itself is not a medical treatment or therapy.

Amino acids are organic compounds that serve as the building blocks of proteins. They consist of a central carbon atom, also known as the alpha carbon, which is bonded to an amino group (-NH2), a carboxyl group (-COOH), a hydrogen atom (H), and a variable side chain (R group). The R group can be composed of various combinations of atoms such as hydrogen, oxygen, sulfur, nitrogen, and carbon, which determine the unique properties of each amino acid.

There are 20 standard amino acids that are encoded by the genetic code and incorporated into proteins during translation. These include:

1. Alanine (Ala)
2. Arginine (Arg)
3. Asparagine (Asn)
4. Aspartic acid (Asp)
5. Cysteine (Cys)
6. Glutamine (Gln)
7. Glutamic acid (Glu)
8. Glycine (Gly)
9. Histidine (His)
10. Isoleucine (Ile)
11. Leucine (Leu)
12. Lysine (Lys)
13. Methionine (Met)
14. Phenylalanine (Phe)
15. Proline (Pro)
16. Serine (Ser)
17. Threonine (Thr)
18. Tryptophan (Trp)
19. Tyrosine (Tyr)
20. Valine (Val)

Additionally, there are several non-standard or modified amino acids that can be incorporated into proteins through post-translational modifications, such as hydroxylation, methylation, and phosphorylation. These modifications expand the functional diversity of proteins and play crucial roles in various cellular processes.

Amino acids are essential for numerous biological functions, including protein synthesis, enzyme catalysis, neurotransmitter production, energy metabolism, and immune response regulation. Some amino acids can be synthesized by the human body (non-essential), while others must be obtained through dietary sources (essential).

Cystathionine gamma-lyase (CSE or CGL) is an enzyme that plays a role in the metabolism of sulfur-containing amino acids, specifically methionine and cysteine. It catalyzes the conversion of cystathionine to cysteine, releasing Ī±-ketobutyrate and ammonia as byproducts. This reaction also results in the formation of hydrogen sulfide (H2S), a gaseous signaling molecule that has been implicated in various physiological and pathophysiological processes.

Cystathionine gamma-lyase is primarily expressed in the liver, kidney, and brain, and its activity is regulated by several factors, including the availability of its substrates and allosteric modulators like S-adenosylmethionine (SAM) and homocysteine. Dysregulation of CSE has been associated with various diseases, such as cardiovascular disorders, neurodegenerative conditions, and cancer. Therefore, understanding the function and regulation of cystathionine gamma-lyase is crucial for developing novel therapeutic strategies targeting these diseases.

A lyase is a type of enzyme that catalyzes the breaking of various chemical bonds in a molecule, often resulting in the formation of two new molecules. Lyases differ from other types of enzymes, such as hydrolases and oxidoreductases, because they create double bonds or rings as part of their reaction mechanism.

In the context of medical terminology, lyases are not typically discussed on their own, but rather as a type of enzyme that can be involved in various biochemical reactions within the body. For example, certain lyases play a role in the metabolism of carbohydrates, lipids, and amino acids, among other molecules.

One specific medical application of lyase enzymes is in the diagnosis of certain genetic disorders. For instance, individuals with hereditary fructose intolerance (HFI) lack the enzyme aldolase B, which is a type of lyase that helps break down fructose in the liver. By measuring the activity of aldolase B in a patient's blood or tissue sample, doctors can diagnose HFI and recommend appropriate dietary restrictions to manage the condition.

Overall, while lyases are not a medical diagnosis or condition themselves, they play important roles in various biochemical processes within the body and can be useful in the diagnosis of certain genetic disorders.

Secondary protein structure refers to the local spatial arrangement of amino acid chains in a protein, typically described as regular repeating patterns held together by hydrogen bonds. The two most common types of secondary structures are the alpha-helix (Ī±-helix) and the beta-pleated sheet (Ī²-sheet). In an Ī±-helix, the polypeptide chain twists around itself in a helical shape, with each backbone atom forming a hydrogen bond with the fourth amino acid residue along the chain. This forms a rigid rod-like structure that is resistant to bending or twisting forces. In Ī²-sheets, adjacent segments of the polypeptide chain run parallel or antiparallel to each other and are connected by hydrogen bonds, forming a pleated sheet-like arrangement. These secondary structures provide the foundation for the formation of tertiary and quaternary protein structures, which determine the overall three-dimensional shape and function of the protein.

Electrophoresis, polyacrylamide gel (EPG) is a laboratory technique used to separate and analyze complex mixtures of proteins or nucleic acids (DNA or RNA) based on their size and electrical charge. This technique utilizes a matrix made of cross-linked polyacrylamide, a type of gel, which provides a stable and uniform environment for the separation of molecules.

In this process:

1. The polyacrylamide gel is prepared by mixing acrylamide monomers with a cross-linking agent (bis-acrylamide) and a catalyst (ammonium persulfate) in the presence of a buffer solution.
2. The gel is then poured into a mold and allowed to polymerize, forming a solid matrix with uniform pore sizes that depend on the concentration of acrylamide used. Higher concentrations result in smaller pores, providing better resolution for separating smaller molecules.
3. Once the gel has set, it is placed in an electrophoresis apparatus containing a buffer solution. Samples containing the mixture of proteins or nucleic acids are loaded into wells on the top of the gel.
4. An electric field is applied across the gel, causing the negatively charged molecules to migrate towards the positive electrode (anode) while positively charged molecules move toward the negative electrode (cathode). The rate of migration depends on the size, charge, and shape of the molecules.
5. Smaller molecules move faster through the gel matrix and will migrate farther from the origin compared to larger molecules, resulting in separation based on size. Proteins and nucleic acids can be selectively stained after electrophoresis to visualize the separated bands.

EPG is widely used in various research fields, including molecular biology, genetics, proteomics, and forensic science, for applications such as protein characterization, DNA fragment analysis, cloning, mutation detection, and quality control of nucleic acid or protein samples.

Endopeptidases are a type of enzyme that breaks down proteins by cleaving peptide bonds inside the polypeptide chain. They are also known as proteinases or endoproteinases. These enzymes work within the interior of the protein molecule, cutting it at specific points along its length, as opposed to exopeptidases, which remove individual amino acids from the ends of the protein chain.

Endopeptidases play a crucial role in various biological processes, such as digestion, blood coagulation, and programmed cell death (apoptosis). They are classified based on their catalytic mechanism and the structure of their active site. Some examples of endopeptidase families include serine proteases, cysteine proteases, aspartic proteases, and metalloproteases.

It is important to note that while endopeptidases are essential for normal physiological functions, they can also contribute to disease processes when their activity is unregulated or misdirected. For instance, excessive endopeptidase activity has been implicated in the pathogenesis of neurodegenerative disorders, cancer, and inflammatory conditions.

Alkylation, in the context of medical chemistry and toxicology, refers to the process of introducing an alkyl group (a chemical moiety made up of a carbon atom bonded to one or more hydrogen atoms) into a molecule, typically a biomolecule such as a protein or DNA. This process can occur through various mechanisms, including chemical reactions with alkylating agents.

In the context of cancer therapy, alkylation is used to describe a class of chemotherapeutic drugs known as alkylating agents, which work by introducing alkyl groups onto DNA molecules in rapidly dividing cells. This can lead to cross-linking of DNA strands and other forms of DNA damage, ultimately inhibiting cell division and leading to the death of cancer cells. However, these agents can also affect normal cells, leading to side effects such as nausea, hair loss, and increased risk of infection.

It's worth noting that alkylation can also occur through non-chemical means, such as in certain types of radiation therapy where high-energy particles can transfer energy to electrons in biological molecules, leading to the formation of reactive radicals that can react with and alkylate DNA.

Thioredoxins are a group of small proteins that contain a redox-active disulfide bond and play a crucial role in the redox regulation of cellular processes. They function as electron donors and help to maintain the intracellular reducing environment by reducing disulfide bonds in other proteins, thereby regulating their activity. Thioredoxins also have antioxidant properties and protect cells from oxidative stress by scavenging reactive oxygen species (ROS) and repairing oxidatively damaged proteins. They are widely distributed in various organisms, including bacteria, plants, and animals, and are involved in many physiological processes such as DNA synthesis, protein folding, and apoptosis.

I'm sorry for any confusion, but "Sulfenic Acids" is not a term used in medical definitions. Sulfenic acids are organic compounds that contain a functional group with the structure R-SOH, where R represents an alkyl or aryl group. They are important intermediates in organic chemistry and biochemistry, but they are not directly related to medical terminology or human health conditions.

Catalysis is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst, which remains unchanged at the end of the reaction. A catalyst lowers the activation energy required for the reaction to occur, thereby allowing the reaction to proceed more quickly and efficiently. This can be particularly important in biological systems, where enzymes act as catalysts to speed up metabolic reactions that are essential for life.

Sulfur-containing amino acids are a type of amino acid that contain sulfur atoms in their side chains. There are three sulfur-containing amino acids that are considered essential for human health: methionine, cysteine, and homocysteine.

Methionine is an essential amino acid, which means that it cannot be synthesized by the human body and must be obtained through the diet. It contains a sulfur atom in its side chain and plays important roles in various biological processes, including methylation reactions, protein synthesis, and detoxification.

Cysteine is a semi-essential amino acid, which means that it can be synthesized by the human body under normal conditions but may become essential during periods of growth or illness. It contains a sulfhydryl group (-SH) in its side chain, which allows it to form disulfide bonds with other cysteine residues and contribute to the stability and structure of proteins.

Homocysteine is a non-proteinogenic amino acid that is derived from methionine metabolism. It contains a sulfur atom in its side chain and has been linked to various health problems, including cardiovascular disease, when present at elevated levels in the blood.

Other sulfur-containing amino acids include taurine, which is not incorporated into proteins but plays important roles in bile acid conjugation, antioxidant defense, and neuromodulation, and cystathionine, which is an intermediate in methionine metabolism.

Bacterial proteins are a type of protein that are produced by bacteria as part of their structural or functional components. These proteins can be involved in various cellular processes, such as metabolism, DNA replication, transcription, and translation. They can also play a role in bacterial pathogenesis, helping the bacteria to evade the host's immune system, acquire nutrients, and multiply within the host.

Bacterial proteins can be classified into different categories based on their function, such as:

1. Enzymes: Proteins that catalyze chemical reactions in the bacterial cell.
2. Structural proteins: Proteins that provide structural support and maintain the shape of the bacterial cell.
3. Signaling proteins: Proteins that help bacteria to communicate with each other and coordinate their behavior.
4. Transport proteins: Proteins that facilitate the movement of molecules across the bacterial cell membrane.
5. Toxins: Proteins that are produced by pathogenic bacteria to damage host cells and promote infection.
6. Surface proteins: Proteins that are located on the surface of the bacterial cell and interact with the environment or host cells.

Understanding the structure and function of bacterial proteins is important for developing new antibiotics, vaccines, and other therapeutic strategies to combat bacterial infections.

Hydrogen-ion concentration, also known as pH, is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (to the base 10) of the hydrogen ion activity in a solution. The standard unit of measurement is the pH unit. A pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.

In medical terms, hydrogen-ion concentration is important for maintaining homeostasis within the body. For example, in the stomach, a high hydrogen-ion concentration (low pH) is necessary for the digestion of food. However, in other parts of the body such as blood, a high hydrogen-ion concentration can be harmful and lead to acidosis. Conversely, a low hydrogen-ion concentration (high pH) in the blood can lead to alkalosis. Both acidosis and alkalosis can have serious consequences on various organ systems if not corrected.

Post-translational protein processing refers to the modifications and changes that proteins undergo after their synthesis on ribosomes, which are complex molecular machines responsible for protein synthesis. These modifications occur through various biochemical processes and play a crucial role in determining the final structure, function, and stability of the protein.

The process begins with the translation of messenger RNA (mRNA) into a linear polypeptide chain, which is then subjected to several post-translational modifications. These modifications can include:

1. Proteolytic cleavage: The removal of specific segments or domains from the polypeptide chain by proteases, resulting in the formation of mature, functional protein subunits.
2. Chemical modifications: Addition or modification of chemical groups to the side chains of amino acids, such as phosphorylation (addition of a phosphate group), glycosylation (addition of sugar moieties), methylation (addition of a methyl group), acetylation (addition of an acetyl group), and ubiquitination (addition of a ubiquitin protein).
3. Disulfide bond formation: The oxidation of specific cysteine residues within the polypeptide chain, leading to the formation of disulfide bonds between them. This process helps stabilize the three-dimensional structure of proteins, particularly in extracellular environments.
4. Folding and assembly: The acquisition of a specific three-dimensional conformation by the polypeptide chain, which is essential for its function. Chaperone proteins assist in this process to ensure proper folding and prevent aggregation.
5. Protein targeting: The directed transport of proteins to their appropriate cellular locations, such as the nucleus, mitochondria, endoplasmic reticulum, or plasma membrane. This is often facilitated by specific signal sequences within the protein that are recognized and bound by transport machinery.

Collectively, these post-translational modifications contribute to the functional diversity of proteins in living organisms, allowing them to perform a wide range of cellular processes, including signaling, catalysis, regulation, and structural support.

A catalytic domain is a portion or region within a protein that contains the active site, where the chemical reactions necessary for the protein's function are carried out. This domain is responsible for the catalysis of biological reactions, hence the name "catalytic domain." The catalytic domain is often composed of specific amino acid residues that come together to form the active site, creating a unique three-dimensional structure that enables the protein to perform its specific function.

In enzymes, for example, the catalytic domain contains the residues that bind and convert substrates into products through chemical reactions. In receptors, the catalytic domain may be involved in signal transduction or other regulatory functions. Understanding the structure and function of catalytic domains is crucial to understanding the mechanisms of protein function and can provide valuable insights for drug design and therapeutic interventions.

A cell line is a culture of cells that are grown in a laboratory for use in research. These cells are usually taken from a single cell or group of cells, and they are able to divide and grow continuously in the lab. Cell lines can come from many different sources, including animals, plants, and humans. They are often used in scientific research to study cellular processes, disease mechanisms, and to test new drugs or treatments. Some common types of human cell lines include HeLa cells (which come from a cancer patient named Henrietta Lacks), HEK293 cells (which come from embryonic kidney cells), and HUVEC cells (which come from umbilical vein endothelial cells). It is important to note that cell lines are not the same as primary cells, which are cells that are taken directly from a living organism and have not been grown in the lab.

4-Chloromercuribenzenesulfonate is a chemical compound with the formula C6H5ClHgSO3. It is an organomercury compound, where mercury is bonded to a phenyl ring and a sulfonate group. This compound is an white crystalline powder that is soluble in water and denser than water.

It has been used historically as a diuretic and antiseptic, but its use in medicine has been discontinued due to the toxicity of mercury. Exposure to mercury can have serious health consequences, including damage to the nervous system, kidneys, and digestive system. Therefore, handling and disposal of 4-chloromercuribenzenesulfonate should be done with caution and in accordance with local regulations for hazardous materials.

Acetylcysteine is a medication that is used for its antioxidant effects and to help loosen thick mucus in the lungs. It is commonly used to treat conditions such as chronic bronchitis, emphysema, and cystic fibrosis. Acetylcysteine is also known by the brand names Mucomyst and Accolate. It works by thinning and breaking down mucus in the airways, making it easier to cough up and clear the airways. Additionally, acetylcysteine is an antioxidant that helps to protect cells from damage caused by free radicals. It is available as a oral tablet, liquid, or inhaled medication.

Osteonectin, also known as SPARC (Secreted Protein Acidic and Rich in Cysteine), is a non-collagenous protein found in the extracellular matrix of bone and other tissues. It plays a crucial role in bone mineralization, collagen fibrillogenesis, and tissue remodeling by interacting with various molecules such as collagens, growth factors, and integrins. Osteonectin is involved in regulating cell adhesion, proliferation, differentiation, and apoptosis during bone development, repair, and homeostasis.

High-performance liquid chromatography (HPLC) is a type of chromatography that separates and analyzes compounds based on their interactions with a stationary phase and a mobile phase under high pressure. The mobile phase, which can be a gas or liquid, carries the sample mixture through a column containing the stationary phase.

In HPLC, the mobile phase is a liquid, and it is pumped through the column at high pressures (up to several hundred atmospheres) to achieve faster separation times and better resolution than other types of liquid chromatography. The stationary phase can be a solid or a liquid supported on a solid, and it interacts differently with each component in the sample mixture, causing them to separate as they travel through the column.

HPLC is widely used in analytical chemistry, pharmaceuticals, biotechnology, and other fields to separate, identify, and quantify compounds present in complex mixtures. It can be used to analyze a wide range of substances, including drugs, hormones, vitamins, pigments, flavors, and pollutants. HPLC is also used in the preparation of pure samples for further study or use.

Lipoylation is the post-translational modification of proteins by attaching lipoic acid (also known as Ī±-lipoic acid or octanoic acid) to specific lysine residues in the protein. This process plays a crucial role in mitochondrial energy metabolism, particularly in the functioning of multi-enzyme complexes involved in the citric acid cycle and oxidative phosphorylation.

The lipoic acid cofactor is covalently attached to the target proteins by enzymes called lipoyltransferases. Once attached, lipoic acid can undergo reversible oxidation-reduction reactions, which facilitate the transfer of electrons and acetyl groups during metabolic processes. These redox reactions are essential for the proper functioning of critical mitochondrial enzymes such as pyruvate dehydrogenase complex (PDH), Ī±-ketoglutarate dehydrogenase complex (KGDHC), and branched-chain ketoacid dehydrogenase complex (BCKDC).

Dysregulation of lipoylation has been implicated in various diseases, including neurodegenerative disorders, metabolic conditions, and cancer. Therefore, understanding the molecular mechanisms underlying lipoylation is important for developing potential therapeutic strategies to target these diseases.

A conserved sequence in the context of molecular biology refers to a pattern of nucleotides (in DNA or RNA) or amino acids (in proteins) that has remained relatively unchanged over evolutionary time. These sequences are often functionally important and are highly conserved across different species, indicating strong selection pressure against changes in these regions.

In the case of protein-coding genes, the corresponding amino acid sequence is deduced from the DNA sequence through the genetic code. Conserved sequences in proteins may indicate structurally or functionally important regions, such as active sites or binding sites, that are critical for the protein's activity. Similarly, conserved non-coding sequences in DNA may represent regulatory elements that control gene expression.

Identifying conserved sequences can be useful for inferring evolutionary relationships between species and for predicting the function of unknown genes or proteins.

Glutamate-cysteine ligase (GCL) is an essential enzyme in the biosynthesis of glutathione, a major antioxidant in cells. It catalyzes the reaction between glutamate and cysteine to form Ī³-glutamylcysteine, which is then combined with glycine by glutathione synthetase to produce glutathione.

GCL has two subunits: a catalytic subunit (GCLC) and a modulatory subunit (GCLM). The former contains the active site for the formation of the peptide bond between glutamate and cysteine, while the latter regulates the activity of GCLC by affecting its sensitivity to feedback inhibition by glutathione.

The proper functioning of GCL is critical for maintaining cellular redox homeostasis and protecting against oxidative stress, making it a potential target for therapeutic intervention in various diseases associated with oxidative damage, such as neurodegenerative disorders, cancer, and aging-related conditions.

Oxidoreductases acting on sulfur group donors are a class of enzymes that catalyze redox reactions involving sulfur group donors. These enzymes play a crucial role in various biological processes, such as the metabolism of sulfur-containing compounds and the detoxification of xenobiotics.

The term "oxidoreductase" refers to any enzyme that catalyzes an oxidation-reduction reaction, where one molecule is oxidized (loses electrons) and another is reduced (gains electrons). In the case of oxidoreductases acting on sulfur group donors, the sulfur atom in the substrate serves as the electron donor.

The systematic name for this class of enzymes follows a specific format: "donor:acceptor oxidoreductase." The donor is the sulfur-containing compound that donates electrons, and the acceptor is the molecule that accepts the electrons. For example, the enzyme that catalyzes the reaction between glutathione (GSH) and a variety of electrophiles is called glutathione transferase, or GST (donor:acceptor oxidoreductase).

These enzymes are further classified into subclasses based on the type of acceptor involved in the reaction. Examples include:

* EC 1.8.1: Oxidoreductases acting on CH-NH2 group donors
* EC 1.8.3: Oxidoreductases acting on CH or CH2 groups
* EC 1.8.4: Oxidoreductases acting on the CH-CH group of donors
* EC 1.8.5: Oxidoreductases acting on a sulfur group of donors
* EC 1.8.6: Oxidoreductases acting on NADH or NADPH

The subclass EC 1.8.5, oxidoreductases acting on a sulfur group of donors, includes enzymes that catalyze redox reactions involving sulfur-containing compounds such as thiols (compounds containing -SH groups), disulfides (-S-S- bonds), and other sulfur-containing functional groups. These enzymes play crucial roles in various biological processes, including detoxification, antioxidant defense, and redox regulation.

Protease inhibitors are a class of antiviral drugs that are used to treat infections caused by retroviruses, such as the human immunodeficiency virus (HIV), which is responsible for causing AIDS. These drugs work by blocking the activity of protease enzymes, which are necessary for the replication and multiplication of the virus within infected cells.

Protease enzymes play a crucial role in the life cycle of retroviruses by cleaving viral polyproteins into functional units that are required for the assembly of new viral particles. By inhibiting the activity of these enzymes, protease inhibitors prevent the virus from replicating and spreading to other cells, thereby slowing down the progression of the infection.

Protease inhibitors are often used in combination with other antiretroviral drugs as part of highly active antiretroviral therapy (HAART) for the treatment of HIV/AIDS. Common examples of protease inhibitors include saquinavir, ritonavir, indinavir, and atazanavir. While these drugs have been successful in improving the outcomes of people living with HIV/AIDS, they can also cause side effects such as nausea, diarrhea, headaches, and lipodystrophy (changes in body fat distribution).

Ethyl methanesulfonate (EMS) is an alkylating agent that is commonly used as a mutagen in genetic research. It works by introducing point mutations into the DNA of organisms, which can then be studied to understand the function of specific genes. EMS modifies DNA by transferring an ethyl group (-C2H5) to the oxygen atom of guanine bases, leading to mispairing during DNA replication and resulting in a high frequency of GC to AT transitions. It is highly toxic and mutagenic, and appropriate safety precautions must be taken when handling this chemical.

Iodoacetates are salts or esters of iodoacetic acid, an organic compound containing iodine. In medicine, iodoacetates have been used as topical antiseptics and anti-inflammatory agents. However, their use is limited due to potential skin irritation and the availability of safer alternatives.

In a broader context, iodoacetates are also known for their chemical properties. They can act as alkylating agents, which means they can react with proteins and enzymes in living organisms, disrupting their function. This property has been exploited in research to study various cellular processes.

Taurine is an organic compound that is widely distributed in animal tissues. It is a conditionally essential amino acid, meaning it can be synthesized by the human body under normal circumstances, but there may be increased requirements during certain periods such as infancy, infection, or illness. Taurine plays important roles in various physiological functions, including bile salt formation, membrane stabilization, neuromodulation, and antioxidation. It is particularly abundant in the brain, heart, retina, and skeletal muscles. In the human body, taurine is synthesized from the amino acids cysteine and methionine with the aid of vitamin B6.

Taurine can also be found in certain foods like meat, fish, and dairy products, as well as in energy drinks, where it is often added as a supplement for its potential performance-enhancing effects. However, there is ongoing debate about the safety and efficacy of taurine supplementation in healthy individuals.

Cystatin B is a type of protease inhibitor that belongs to the cystatin superfamily. It is primarily produced in the central nervous system and is found in various body fluids, including cerebrospinal fluid and urine. Cystatin B plays a crucial role in regulating protein catabolism by inhibiting lysosomal cysteine proteases, which are enzymes that break down proteins.

Defects or mutations in the gene that encodes for cystatin B have been associated with a rare inherited neurodegenerative disorder known as Uner Tan Syndrome (UTS). UTS is characterized by language impairment, mental retardation, and distinctive facial features. The exact mechanism by which cystatin B deficiency leads to this disorder is not fully understood, but it is thought to involve the dysregulation of protein catabolism in neurons, leading to neurotoxicity and neurodegeneration.

A peptide fragment is a short chain of amino acids that is derived from a larger peptide or protein through various biological or chemical processes. These fragments can result from the natural breakdown of proteins in the body during regular physiological processes, such as digestion, or they can be produced experimentally in a laboratory setting for research or therapeutic purposes.

Peptide fragments are often used in research to map the structure and function of larger peptides and proteins, as well as to study their interactions with other molecules. In some cases, peptide fragments may also have biological activity of their own and can be developed into drugs or diagnostic tools. For example, certain peptide fragments derived from hormones or neurotransmitters may bind to receptors in the body and mimic or block the effects of the full-length molecule.

A dipeptide is a type of molecule that is formed by the condensation of two amino acids. In this process, the carboxyl group (-COOH) of one amino acid combines with the amino group (-NH2) of another amino acid, releasing a water molecule and forming a peptide bond.

The resulting molecule contains two amino acids joined together by a single peptide bond, which is a type of covalent bond that forms between the carboxyl group of one amino acid and the amino group of another. Dipeptides are relatively simple molecules compared to larger polypeptides or proteins, which can contain hundreds or even thousands of amino acids linked together by multiple peptide bonds.

Dipeptides have a variety of biological functions in the body, including serving as building blocks for larger proteins and playing important roles in various physiological processes. Some dipeptides also have potential therapeutic uses, such as in the treatment of hypertension or muscle wasting disorders.

Histidine is an essential amino acid, meaning it cannot be synthesized by the human body and must be obtained through dietary sources. Its chemical formula is C6H9N3O2. Histidine plays a crucial role in several physiological processes, including:

1. Protein synthesis: As an essential amino acid, histidine is required for the production of proteins, which are vital components of various tissues and organs in the body.

2. Hemoglobin synthesis: Histidine is a key component of hemoglobin, the protein in red blood cells responsible for carrying oxygen throughout the body. The imidazole side chain of histidine acts as a proton acceptor/donor, facilitating the release and uptake of oxygen by hemoglobin.

3. Acid-base balance: Histidine is involved in maintaining acid-base homeostasis through its role in the biosynthesis of histamine, which is a critical mediator of inflammatory responses and allergies. The decarboxylation of histidine results in the formation of histamine, which can increase vascular permeability and modulate immune responses.

4. Metal ion binding: Histidine has a high affinity for metal ions such as zinc, copper, and iron. This property allows histidine to participate in various enzymatic reactions and maintain the structural integrity of proteins.

5. Antioxidant defense: Histidine-containing dipeptides, like carnosine and anserine, have been shown to exhibit antioxidant properties by scavenging reactive oxygen species (ROS) and chelating metal ions. These compounds may contribute to the protection of proteins and DNA from oxidative damage.

Dietary sources of histidine include meat, poultry, fish, dairy products, and wheat germ. Histidine deficiency is rare but can lead to growth retardation, anemia, and impaired immune function.

Mass spectrometry (MS) is an analytical technique used to identify and quantify the chemical components of a mixture or compound. It works by ionizing the sample, generating charged molecules or fragments, and then measuring their mass-to-charge ratio in a vacuum. The resulting mass spectrum provides information about the molecular weight and structure of the analytes, allowing for identification and characterization.

In simpler terms, mass spectrometry is a method used to determine what chemicals are present in a sample and in what quantities, by converting the chemicals into ions, measuring their masses, and generating a spectrum that shows the relative abundances of each ion type.

In the context of medicine and toxicology, sulfides refer to inorganic or organic compounds containing the sulfide ion (S2-). Sulfides can be found in various forms such as hydrogen sulfide (H2S), metal sulfides, and organic sulfides (also known as thioethers).

Hydrogen sulfide is a toxic gas with a characteristic rotten egg smell. It can cause various adverse health effects, including respiratory irritation, headaches, nausea, and, at high concentrations, loss of consciousness or even death. Metal sulfides, such as those found in some minerals, can also be toxic and may release hazardous sulfur dioxide (SO2) when heated or reacted with acidic substances.

Organic sulfides, on the other hand, are a class of organic compounds containing a sulfur atom bonded to two carbon atoms. They can occur naturally in some plants and animals or be synthesized in laboratories. Some organic sulfides have medicinal uses, while others may pose health risks depending on their concentration and route of exposure.

It is important to note that the term "sulfide" has different meanings in various scientific contexts, so it is essential to consider the specific context when interpreting this term.

Cathepsin K is a proteolytic enzyme, which belongs to the family of papain-like cysteine proteases. It is primarily produced by osteoclasts, which are specialized cells responsible for bone resorption. Cathepsin K plays a crucial role in the degradation and remodeling of the extracellular matrix, particularly in bone tissue.

This enzyme is capable of breaking down various proteins, including collagen, elastin, and proteoglycans, which are major components of the bone matrix. By doing so, cathepsin K helps osteoclasts to dissolve and remove mineralized and non-mineralized bone matrix during the process of bone resorption.

Apart from its function in bone metabolism, cathepsin K has also been implicated in several pathological conditions, such as osteoporosis, rheumatoid arthritis, and tumor metastasis to bones. Inhibitors of cathepsin K are being investigated as potential therapeutic agents for the treatment of these disorders.

Dimerization is a process in which two molecules, usually proteins or similar structures, bind together to form a larger complex. This can occur through various mechanisms, such as the formation of disulfide bonds, hydrogen bonding, or other non-covalent interactions. Dimerization can play important roles in cell signaling, enzyme function, and the regulation of gene expression.

In the context of medical research and therapy, dimerization is often studied in relation to specific proteins that are involved in diseases such as cancer. For example, some drugs have been developed to target and inhibit the dimerization of certain proteins, with the goal of disrupting their function and slowing or stopping the progression of the disease.

Zinc is an essential mineral that is vital for the functioning of over 300 enzymes and involved in various biological processes in the human body, including protein synthesis, DNA synthesis, immune function, wound healing, and cell division. It is a component of many proteins and participates in the maintenance of structural integrity and functionality of proteins. Zinc also plays a crucial role in maintaining the sense of taste and smell.

The recommended daily intake of zinc varies depending on age, sex, and life stage. Good dietary sources of zinc include red meat, poultry, seafood, beans, nuts, dairy products, and fortified cereals. Zinc deficiency can lead to various health problems, including impaired immune function, growth retardation, and developmental delays in children. On the other hand, excessive intake of zinc can also have adverse effects on health, such as nausea, vomiting, and impaired immune function.

Iron-sulfur proteins are a group of metalloproteins that contain iron and sulfur atoms in their active centers. These clusters of iron and sulfur atoms, also known as iron-sulfur clusters, can exist in various forms, including Fe-S, 2Fe-2S, 3Fe-4S, and 4Fe-4S structures. The iron atoms are coordinated to the protein through cysteine residues, while the sulfur atoms can be in the form of sulfide (S2-) or sulfane (-S-).

These proteins play crucial roles in many biological processes, such as electron transfer, redox reactions, and enzyme catalysis. They are found in various organisms, from bacteria to humans, and are involved in a wide range of cellular functions, including energy metabolism, photosynthesis, nitrogen fixation, and DNA repair.

Iron-sulfur proteins can be classified into several categories based on their structure and function, such as ferredoxins, Rieske proteins, high-potential iron-sulfur proteins (HiPIPs), and radical SAM enzymes. Dysregulation or mutations in iron-sulfur protein genes have been linked to various human diseases, including neurodegenerative disorders, cancer, and mitochondrial disorders.

Peptides are short chains of amino acid residues linked by covalent bonds, known as peptide bonds. They are formed when two or more amino acids are joined together through a condensation reaction, which results in the elimination of a water molecule and the formation of an amide bond between the carboxyl group of one amino acid and the amino group of another.

Peptides can vary in length from two to about fifty amino acids, and they are often classified based on their size. For example, dipeptides contain two amino acids, tripeptides contain three, and so on. Oligopeptides typically contain up to ten amino acids, while polypeptides can contain dozens or even hundreds of amino acids.

Peptides play many important roles in the body, including serving as hormones, neurotransmitters, enzymes, and antibiotics. They are also used in medical research and therapeutic applications, such as drug delivery and tissue engineering.

Peroxiredoxins (Prx) are a family of peroxidases that play a crucial role in cellular defense against oxidative stress. They catalyze the reduction of hydrogen peroxide, organic hydroperoxides, and peroxynitrite, thereby protecting cells from potentially harmful effects of these reactive oxygen and nitrogen species.

Peroxiredoxins are ubiquitously expressed in various cellular compartments, including the cytosol, mitochondria, and nucleus. They contain a conserved catalytic cysteine residue that gets oxidized during the reduction of peroxides, which is then reduced back to its active form by thioredoxins or other reducing agents.

Dysregulation of peroxiredoxin function has been implicated in various pathological conditions, including cancer, neurodegenerative diseases, and inflammatory disorders. Therefore, understanding the role of peroxiredoxins in cellular redox homeostasis is essential for developing novel therapeutic strategies to treat oxidative stress-related diseases.

Complementary DNA (cDNA) is a type of DNA that is synthesized from a single-stranded RNA molecule through the process of reverse transcription. In this process, the enzyme reverse transcriptase uses an RNA molecule as a template to synthesize a complementary DNA strand. The resulting cDNA is therefore complementary to the original RNA molecule and is a copy of its coding sequence, but it does not contain non-coding regions such as introns that are present in genomic DNA.

Complementary DNA is often used in molecular biology research to study gene expression, protein function, and other genetic phenomena. For example, cDNA can be used to create cDNA libraries, which are collections of cloned cDNA fragments that represent the expressed genes in a particular cell type or tissue. These libraries can then be screened for specific genes or gene products of interest. Additionally, cDNA can be used to produce recombinant proteins in heterologous expression systems, allowing researchers to study the structure and function of proteins that may be difficult to express or purify from their native sources.

Cystathionine is a non-proteinogenic amino acid, which means that it is not used in the synthesis of proteins. It is an intermediate in the biosynthetic pathway that converts the amino acid methionine to cysteine in the body. This process involves the removal of a sulfur atom from methionine, resulting in the formation of cystathionine. Further breakdown of cystathionine leads to the production of cysteine and another amino acid called alpha-ketobutyrate.

Cystathionine plays a crucial role in the metabolism of certain sulfur-containing amino acids, and its levels are regulated by an enzyme called cystathionine beta-synthase (CBS). Genetic defects or deficiencies in this enzyme can result in a disorder known as homocystinuria, which is characterized by the accumulation of homocysteine and methionine in the body and an increased risk of various health complications.

In summary, cystathionine is a biologically important amino acid that functions as an intermediate in the conversion of methionine to cysteine, and its levels are tightly regulated by enzymatic processes in the body.

Protein folding is the process by which a protein molecule naturally folds into its three-dimensional structure, following the synthesis of its amino acid chain. This complex process is determined by the sequence and properties of the amino acids, as well as various environmental factors such as temperature, pH, and the presence of molecular chaperones. The final folded conformation of a protein is crucial for its proper function, as it enables the formation of specific interactions between different parts of the molecule, which in turn define its biological activity. Protein misfolding can lead to various diseases, including neurodegenerative disorders such as Alzheimer's and Parkinson's disease.

Molecular weight, also known as molecular mass, is the mass of a molecule. It is expressed in units of atomic mass units (amu) or daltons (Da). Molecular weight is calculated by adding up the atomic weights of each atom in a molecule. It is a useful property in chemistry and biology, as it can be used to determine the concentration of a substance in a solution, or to calculate the amount of a substance that will react with another in a chemical reaction.

Alanine is an alpha-amino acid that is used in the biosynthesis of proteins. The molecular formula for alanine is C3H7NO2. It is a non-essential amino acid, which means that it can be produced by the human body through the conversion of other nutrients, such as pyruvate, and does not need to be obtained directly from the diet.

Alanine is classified as an aliphatic amino acid because it contains a simple carbon side chain. It is also a non-polar amino acid, which means that it is hydrophobic and tends to repel water. Alanine plays a role in the metabolism of glucose and helps to regulate blood sugar levels. It is also involved in the transfer of nitrogen between tissues and helps to maintain the balance of nitrogen in the body.

In addition to its role as a building block of proteins, alanine is also used as a neurotransmitter in the brain and has been shown to have a calming effect on the nervous system. It is found in many foods, including meats, poultry, fish, eggs, dairy products, and legumes.

X-ray crystallography is a technique used in structural biology to determine the three-dimensional arrangement of atoms in a crystal lattice. In this method, a beam of X-rays is directed at a crystal and diffracts, or spreads out, into a pattern of spots called reflections. The intensity and angle of each reflection are measured and used to create an electron density map, which reveals the position and type of atoms in the crystal. This information can be used to determine the molecular structure of a compound, including its shape, size, and chemical bonds. X-ray crystallography is a powerful tool for understanding the structure and function of biological macromolecules such as proteins and nucleic acids.

Cross-linking reagents are chemical agents that are used to create covalent bonds between two or more molecules, creating a network of interconnected molecules known as a cross-linked structure. In the context of medical and biological research, cross-linking reagents are often used to stabilize protein structures, study protein-protein interactions, and develop therapeutic agents.

Cross-linking reagents work by reacting with functional groups on adjacent molecules, such as amino groups (-NH2) or sulfhydryl groups (-SH), to form a covalent bond between them. This can help to stabilize protein structures and prevent them from unfolding or aggregating.

There are many different types of cross-linking reagents, each with its own specificity and reactivity. Some common examples include glutaraldehyde, formaldehyde, disuccinimidyl suberate (DSS), and bis(sulfosuccinimidyl) suberate (BS3). The choice of cross-linking reagent depends on the specific application and the properties of the molecules being cross-linked.

It is important to note that cross-linking reagents can also have unintended effects, such as modifying or disrupting the function of the proteins they are intended to stabilize. Therefore, it is essential to use them carefully and with appropriate controls to ensure accurate and reliable results.

Cystatin A is a type of cysteine protease inhibitor that is primarily produced by cells of the immune system. It is a small protein consisting of 120 amino acids and is encoded by the CSTA gene in humans. Cystatin A functions to regulate the activity of cathepsins, which are enzymes that break down proteins in the body.

Cystatin A is mainly found inside cells, where it helps to maintain the balance of cathepsins and prevent excessive protein degradation. However, it can also be released into extracellular spaces under certain conditions, such as inflammation or cell damage. In the extracellular space, cystatin A may help to regulate the activity of cathepsins in the surrounding tissue and contribute to the regulation of immune responses.

Abnormal levels of cystatin A have been associated with various diseases, including cancer, autoimmune disorders, and neurodegenerative diseases. However, more research is needed to fully understand the role of cystatin A in these conditions and its potential as a therapeutic target.

DNA primers are short single-stranded DNA molecules that serve as a starting point for DNA synthesis. They are typically used in laboratory techniques such as the polymerase chain reaction (PCR) and DNA sequencing. The primer binds to a complementary sequence on the DNA template through base pairing, providing a free 3'-hydroxyl group for the DNA polymerase enzyme to add nucleotides and synthesize a new strand of DNA. This allows for specific and targeted amplification or analysis of a particular region of interest within a larger DNA molecule.

Trypsin is a proteolytic enzyme, specifically a serine protease, that is secreted by the pancreas as an inactive precursor, trypsinogen. Trypsinogen is converted into its active form, trypsin, in the small intestine by enterokinase, which is produced by the intestinal mucosa.

Trypsin plays a crucial role in digestion by cleaving proteins into smaller peptides at specific arginine and lysine residues. This enzyme helps to break down dietary proteins into amino acids, allowing for their absorption and utilization by the body. Additionally, trypsin can activate other zymogenic pancreatic enzymes, such as chymotrypsinogen and procarboxypeptidases, thereby contributing to overall protein digestion.

Membrane proteins are a type of protein that are embedded in the lipid bilayer of biological membranes, such as the plasma membrane of cells or the inner membrane of mitochondria. These proteins play crucial roles in various cellular processes, including:

1. Cell-cell recognition and signaling
2. Transport of molecules across the membrane (selective permeability)
3. Enzymatic reactions at the membrane surface
4. Energy transduction and conversion
5. Mechanosensation and signal transduction

Membrane proteins can be classified into two main categories: integral membrane proteins, which are permanently associated with the lipid bilayer, and peripheral membrane proteins, which are temporarily or loosely attached to the membrane surface. Integral membrane proteins can further be divided into three subcategories based on their topology:

1. Transmembrane proteins, which span the entire width of the lipid bilayer with one or more alpha-helices or beta-barrels.
2. Lipid-anchored proteins, which are covalently attached to lipids in the membrane via a glycosylphosphatidylinositol (GPI) anchor or other lipid modifications.
3. Monotopic proteins, which are partially embedded in the membrane and have one or more domains exposed to either side of the bilayer.

Membrane proteins are essential for maintaining cellular homeostasis and are targets for various therapeutic interventions, including drug development and gene therapy. However, their structural complexity and hydrophobicity make them challenging to study using traditional biochemical methods, requiring specialized techniques such as X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and single-particle cryo-electron microscopy (cryo-EM).

Mutagenesis is the process by which the genetic material (DNA or RNA) of an organism is changed in a way that can alter its phenotype, or observable traits. These changes, known as mutations, can be caused by various factors such as chemicals, radiation, or viruses. Some mutations may have no effect on the organism, while others can cause harm, including diseases and cancer. Mutagenesis is a crucial area of study in genetics and molecular biology, with implications for understanding evolution, genetic disorders, and the development of new medical treatments.

Proteins are complex, large molecules that play critical roles in the body's functions. They are made up of amino acids, which are organic compounds that are the building blocks of proteins. Proteins are required for the structure, function, and regulation of the body's tissues and organs. They are essential for the growth, repair, and maintenance of body tissues, and they play a crucial role in many biological processes, including metabolism, immune response, and cellular signaling. Proteins can be classified into different types based on their structure and function, such as enzymes, hormones, antibodies, and structural proteins. They are found in various foods, especially animal-derived products like meat, dairy, and eggs, as well as plant-based sources like beans, nuts, and grains.

Oxidoreductases are a class of enzymes that catalyze oxidation-reduction reactions, which involve the transfer of electrons from one molecule (the reductant) to another (the oxidant). These enzymes play a crucial role in various biological processes, including energy production, metabolism, and detoxification.

The oxidoreductase-catalyzed reaction typically involves the donation of electrons from a reducing agent (donor) to an oxidizing agent (acceptor), often through the transfer of hydrogen atoms or hydride ions. The enzyme itself does not undergo any permanent chemical change during this process, but rather acts as a catalyst to lower the activation energy required for the reaction to occur.

Oxidoreductases are classified and named based on the type of electron donor or acceptor involved in the reaction. For example, oxidoreductases that act on the CH-OH group of donors are called dehydrogenases, while those that act on the aldehyde or ketone groups are called oxidases. Other examples include reductases, peroxidases, and catalases.

Understanding the function and regulation of oxidoreductases is important for understanding various physiological processes and developing therapeutic strategies for diseases associated with impaired redox homeostasis, such as cancer, neurodegenerative disorders, and cardiovascular disease.

Hydrolysis is a chemical process, not a medical one. However, it is relevant to medicine and biology.

Hydrolysis is the breakdown of a chemical compound due to its reaction with water, often resulting in the formation of two or more simpler compounds. In the context of physiology and medicine, hydrolysis is a crucial process in various biological reactions, such as the digestion of food molecules like proteins, carbohydrates, and fats. Enzymes called hydrolases catalyze these hydrolysis reactions to speed up the breakdown process in the body.

"Cattle" is a term used in the agricultural and veterinary fields to refer to domesticated animals of the genus *Bos*, primarily *Bos taurus* (European cattle) and *Bos indicus* (Zebu). These animals are often raised for meat, milk, leather, and labor. They are also known as bovines or cows (for females), bulls (intact males), and steers/bullocks (castrated males). However, in a strict medical definition, "cattle" does not apply to humans or other animals.

Calpains are a family of calcium-dependent cysteine proteases that play important roles in various cellular processes, including signal transduction, cell death, and remodeling of the cytoskeleton. They are present in most tissues and can be activated by an increase in intracellular calcium levels. There are at least 15 different calpain isoforms identified in humans, which are categorized into two groups based on their calcium requirements for activation: classical calpains (calpain-1 and calpain-2) and non-classical calpains (calpain-3 to calpain-15). Dysregulation of calpain activity has been implicated in several pathological conditions, such as neurodegenerative diseases, muscular dystrophies, and cancer.

Indicators and reagents are terms commonly used in the field of clinical chemistry and laboratory medicine. Here are their definitions:

1. Indicator: An indicator is a substance that changes its color or other physical properties in response to a chemical change, such as a change in pH, oxidation-reduction potential, or the presence of a particular ion or molecule. Indicators are often used in laboratory tests to monitor or signal the progress of a reaction or to indicate the end point of a titration. A familiar example is the use of phenolphthalein as a pH indicator in acid-base titrations, which turns pink in basic solutions and colorless in acidic solutions.

2. Reagent: A reagent is a substance that is added to a system (such as a sample or a reaction mixture) to bring about a chemical reaction, test for the presence or absence of a particular component, or measure the concentration of a specific analyte. Reagents are typically chemicals with well-defined and consistent properties, allowing them to be used reliably in analytical procedures. Examples of reagents include enzymes, antibodies, dyes, metal ions, and organic compounds. In laboratory settings, reagents are often prepared and standardized according to strict protocols to ensure their quality and performance in diagnostic tests and research applications.

Glycine is a simple amino acid that plays a crucial role in the body. According to the medical definition, glycine is an essential component for the synthesis of proteins, peptides, and other biologically important compounds. It is also involved in various metabolic processes, such as the production of creatine, which supports muscle function, and the regulation of neurotransmitters, affecting nerve impulse transmission and brain function. Glycine can be found as a free form in the body and is also present in many dietary proteins.

A cell membrane, also known as the plasma membrane, is a thin semi-permeable phospholipid bilayer that surrounds all cells in animals, plants, and microorganisms. It functions as a barrier to control the movement of substances in and out of the cell, allowing necessary molecules such as nutrients, oxygen, and signaling molecules to enter while keeping out harmful substances and waste products. The cell membrane is composed mainly of phospholipids, which have hydrophilic (water-loving) heads and hydrophobic (water-fearing) tails. This unique structure allows the membrane to be flexible and fluid, yet selectively permeable. Additionally, various proteins are embedded in the membrane that serve as channels, pumps, receptors, and enzymes, contributing to the cell's overall functionality and communication with its environment.

Cathepsin F is a lysosomal cysteine protease that belongs to the papain family. It is primarily expressed in hematopoietic cells, including monocytes, macrophages, and dendritic cells. Cathepsin F plays a role in various physiological processes, such as antigen presentation, bone remodeling, and extracellular matrix degradation. It is also implicated in several pathological conditions, such as cancer, neurodegenerative disorders, and infectious diseases.

Cathepsin F has a broad substrate specificity and can cleave various proteins, including collagen, elastin, and casein. Its activity is tightly regulated by endogenous inhibitors, such as cystatins and stefins, to prevent excessive protein degradation and tissue damage.

In summary, Cathepsin F is a lysosomal enzyme involved in various physiological and pathological processes, with a broad substrate specificity and regulatory mechanisms.

Glutaredoxins (Grxs) are small, ubiquitous proteins that belong to the thioredoxin superfamily. They play a crucial role in maintaining the redox balance within cells by catalyzing the reversible reduction of disulfide bonds and mixed disulfides between protein thiols and low molecular weight compounds, using glutathione (GSH) as a reducing cofactor.

Glutaredoxins are involved in various cellular processes, such as:

1. DNA synthesis and repair
2. Protein folding and degradation
3. Antioxidant defense
4. Regulation of enzyme activities
5. Iron-sulfur cluster biogenesis

There are two main classes of glutaredoxins, Grx1 and Grx2, which differ in their active site sequences and functions. In humans, Grx1 is primarily located in the cytosol, while Grx2 is found in both the cytosol and mitochondria.

The medical relevance of glutaredoxins lies in their role as antioxidant proteins that protect cells from oxidative stress and maintain cellular redox homeostasis. Dysregulation of glutaredoxin function has been implicated in several pathological conditions, including neurodegenerative diseases, cancer, and aging-related disorders.

Peptide mapping is a technique used in proteomics and analytical chemistry to analyze and identify the sequence and structure of peptides or proteins. This method involves breaking down a protein into smaller peptide fragments using enzymatic or chemical digestion, followed by separation and identification of these fragments through various analytical techniques such as liquid chromatography (LC) and mass spectrometry (MS).

The resulting peptide map serves as a "fingerprint" of the protein, providing information about its sequence, modifications, and structure. Peptide mapping can be used for a variety of applications, including protein identification, characterization of post-translational modifications, and monitoring of protein degradation or cleavage.

In summary, peptide mapping is a powerful tool in proteomics that enables the analysis and identification of proteins and their modifications at the peptide level.

Ficain is not typically defined in the context of human medicine, but it is a term used in biochemistry and molecular biology. Ficain is a proteolytic enzyme, also known as ficin, that is isolated from the latex of the fig tree (Ficus species). It has the ability to break down other proteins into smaller peptides or individual amino acids by cleaving specific peptide bonds. Ficain is often used in research and industrial applications, such as protein degradation, digestion studies, and biochemical assays.

Transfection is a term used in molecular biology that refers to the process of deliberately introducing foreign genetic material (DNA, RNA or artificial gene constructs) into cells. This is typically done using chemical or physical methods, such as lipofection or electroporation. Transfection is widely used in research and medical settings for various purposes, including studying gene function, producing proteins, developing gene therapies, and creating genetically modified organisms. It's important to note that transfection is different from transduction, which is the process of introducing genetic material into cells using viruses as vectors.

Palmitic acid is a type of saturated fatty acid, which is a common component in many foods and also produced naturally by the human body. Its chemical formula is C16H32O2. It's named after palm trees because it was first isolated from palm oil, although it can also be found in other vegetable oils, animal fats, and dairy products.

In the human body, palmitic acid plays a role in energy production and storage. However, consuming large amounts of this fatty acid has been linked to an increased risk of heart disease due to its association with elevated levels of bad cholesterol (LDL). The World Health Organization recommends limiting the consumption of saturated fats, including palmitic acid, to less than 10% of total energy intake.

Hydrogen peroxide (H2O2) is a colorless, odorless, clear liquid with a slightly sweet taste, although drinking it is harmful and can cause poisoning. It is a weak oxidizing agent and is used as an antiseptic and a bleaching agent. In diluted form, it is used to disinfect wounds and kill bacteria and viruses on the skin; in higher concentrations, it can be used to bleach hair or remove stains from clothing. It is also used as a propellant in rocketry and in certain industrial processes. Chemically, hydrogen peroxide is composed of two hydrogen atoms and two oxygen atoms, and it is structurally similar to water (H2O), with an extra oxygen atom. This gives it its oxidizing properties, as the additional oxygen can be released and used to react with other substances.

Phenanthrolines are a class of compounds that contain a phenanthrene core with two amine groups attached to adjacent carbon atoms. They are known for their ability to form complexes with metal ions and have been widely used in the field of medicinal chemistry as building blocks for pharmaceuticals, particularly in the development of antimalarial drugs such as chloroquine and quinine. Additionally, phenanthrolines have also been explored for their potential use in cancer therapy due to their ability to interfere with DNA replication and transcription. However, it's important to note that specific medical uses and applications of phenanthrolines will depend on the particular compound and its properties.

Maleimides are a class of chemical compounds that contain a maleimide functional group, which is characterized by a five-membered ring containing two carbon atoms and three nitrogen atoms. The double bond in the maleimide ring makes it highly reactive towards nucleophiles, particularly thiol groups found in cysteine residues of proteins.

In medical and biological contexts, maleimides are often used as cross-linking agents to modify or label proteins, peptides, and other biomolecules. For example, maleimide-functionalized probes such as fluorescent dyes, biotin, or radioisotopes can be covalently attached to thiol groups in proteins for various applications, including protein detection, purification, and imaging.

However, it is important to note that maleimides can also react with other nucleophiles such as amines, although at a slower rate. Therefore, careful control of reaction conditions is necessary to ensure specificity towards thiol groups.

Sulfurtransferases are a group of enzymes that catalyze the transfer of a sulfur group from one molecule to another. These enzymes play a crucial role in various biological processes, including the detoxification of harmful compounds and the synthesis of important metabolites. They can be found in many organisms, from bacteria to humans.

In humans, there are several types of sulfurtransferases, including cysteine conjugate beta-lyase, rhodanese, and 3'-phosphoadenosine 5'-phosphosulfate (PAPS) reductase. These enzymes have different substrates and functions, but they all share the ability to transfer a sulfur group from one molecule to another.

For example, rhodanese is an enzyme that transfers a sulfur atom from thiosulfate to cyanide, converting it to less toxic thiocyanate. This reaction is important in the detoxification of cyanide in the body.

Sulfurtransferases are also involved in the synthesis of various metabolites, such as iron-sulfur clusters and molybdenum cofactor, which are essential for the function of many enzymes.

Deficiencies or mutations in sulfurtransferase genes can lead to various diseases and disorders, highlighting their importance in human health.

Cystathionine beta-synthase (CBS) is an enzyme that plays a crucial role in the metabolic pathway responsible for the production of the amino acid cysteine from homocysteine. CBS catalyzes the condensation of serine with homocysteine to form cystathionine, which is subsequently hydrolyzed to cysteine and alpha-ketobutyrate by another enzyme called cystathionine gamma-lyase.

CBS requires the cofactor pyridoxal 5'-phosphate (PLP) for its activity and is primarily located in the liver, where it helps regulate homocysteine levels in the body. Elevated levels of homocysteine have been linked to various health issues, including cardiovascular disease and neurological disorders.

In addition to its role in cysteine synthesis, CBS also contributes to the transsulfuration pathway, which is involved in the detoxification of methionine and the production of glutathione, an essential antioxidant in the body. Genetic mutations in the CBS gene can lead to conditions such as homocystinuria, a rare inherited metabolic disorder characterized by elevated levels of homocysteine and methionine in the blood and urine.

In the context of medicine and biology, sulfates are ions or compounds that contain the sulfate group (SO4āˆ’2). Sulfate is a polyatomic anion with the structure of a sphere. It consists of a central sulfur atom surrounded by four oxygen atoms in a tetrahedral arrangement.

Sulfates can be found in various biological molecules, such as glycosaminoglycans and proteoglycans, which are important components of connective tissue and the extracellular matrix. Sulfate groups play a crucial role in these molecules by providing negative charges that help maintain the structural integrity and hydration of tissues.

In addition to their biological roles, sulfates can also be found in various medications and pharmaceutical compounds. For example, some laxatives contain sulfate salts, such as magnesium sulfate (Epsom salt) or sodium sulfate, which work by increasing the water content in the intestines and promoting bowel movements.

It is important to note that exposure to high levels of sulfates can be harmful to human health, particularly in the form of sulfur dioxide (SO2), a common air pollutant produced by burning fossil fuels. Prolonged exposure to SO2 can cause respiratory problems and exacerbate existing lung conditions.

Diazomethane is a highly reactive, explosive organic compound with the chemical formula CH2N2. It is a colorless gas or pale yellow liquid that is used as a methylating agent in organic synthesis. Diazomethane is prepared by the reaction of nitrosomethane with a base such as potassium hydroxide.

It is important to handle diazomethane with care, as it can be explosive and toxic. It should only be used in well-ventilated areas, and protective equipment such as gloves and safety glasses should be worn. Diazomethane should not be stored for long periods of time, as it can decompose spontaneously and release nitrogen gas.

Diazomethane is used to introduce methyl groups into organic molecules in a process called methylation. It reacts with carboxylic acids to form methyl esters, and with phenols to form methyl ethers. Diazomethane is also used to synthesize other organic compounds such as pyrazoles and triazoles.

It is important to note that the use of diazomethane in the laboratory has declined due to its hazardous nature, and safer alternatives are now available for many of its applications.

Enzyme activation refers to the process by which an enzyme becomes biologically active and capable of carrying out its specific chemical or biological reaction. This is often achieved through various post-translational modifications, such as proteolytic cleavage, phosphorylation, or addition of cofactors or prosthetic groups to the enzyme molecule. These modifications can change the conformation or structure of the enzyme, exposing or creating a binding site for the substrate and allowing the enzymatic reaction to occur.

For example, in the case of proteolytic cleavage, an inactive precursor enzyme, known as a zymogen, is cleaved into its active form by a specific protease. This is seen in enzymes such as trypsin and chymotrypsin, which are initially produced in the pancreas as inactive precursors called trypsinogen and chymotrypsinogen, respectively. Once they reach the small intestine, they are activated by enteropeptidase, a protease that cleaves a specific peptide bond, releasing the active enzyme.

Phosphorylation is another common mechanism of enzyme activation, where a phosphate group is added to a specific serine, threonine, or tyrosine residue on the enzyme by a protein kinase. This modification can alter the conformation of the enzyme and create a binding site for the substrate, allowing the enzymatic reaction to occur.

Enzyme activation is a crucial process in many biological pathways, as it allows for precise control over when and where specific reactions take place. It also provides a mechanism for regulating enzyme activity in response to various signals and stimuli, such as hormones, neurotransmitters, or changes in the intracellular environment.

Pyrrolidonecarboxylic acid, also known as Proline or Prolinic acid, is an organic compound with the formula N-pyrrolidinecarboxylic acid. It is a cyclic amino acid, which means that its side chain is bonded to the rest of the molecule in a ring structure.

Proline is an important constituent of many proteins and plays a crucial role in maintaining the structural integrity of the protein. It is classified as a non-essential amino acid because it can be synthesized by the human body from other amino acids, such as glutamic acid.

Pyrrolidonecarboxylic acid has a variety of uses in medicine and industry, including as a chiral auxiliary in organic synthesis, a building block for pharmaceuticals, and a component in cosmetics and personal care products. It is also used as a buffering agent and a stabilizer in various medical and industrial applications.

Circular dichroism (CD) is a technique used in physics and chemistry to study the structure of molecules, particularly large biological molecules such as proteins and nucleic acids. It measures the difference in absorption of left-handed and right-handed circularly polarized light by a sample. This difference in absorption can provide information about the three-dimensional structure of the molecule, including its chirality or "handedness."

In more technical terms, CD is a form of spectroscopy that measures the differential absorption of left and right circularly polarized light as a function of wavelength. The CD signal is measured in units of millidegrees (mdeg) and can be positive or negative, depending on the type of chromophore and its orientation within the molecule.

CD spectra can provide valuable information about the secondary and tertiary structure of proteins, as well as the conformation of nucleic acids. For example, alpha-helical proteins typically exhibit a strong positive band near 190 nm and two negative bands at around 208 nm and 222 nm, while beta-sheet proteins show a strong positive band near 195 nm and two negative bands at around 217 nm and 175 nm.

CD spectroscopy is a powerful tool for studying the structural changes that occur in biological molecules under different conditions, such as temperature, pH, or the presence of ligands or other molecules. It can also be used to monitor the folding and unfolding of proteins, as well as the binding of drugs or other small molecules to their targets.

Cysteamine is a medication and a naturally occurring aminothiol compound, which is composed of the amino acid cysteine and a sulfhydryl group. It has various uses in medicine, including as a treatment for cystinosis, a rare genetic disorder that causes an accumulation of cystine crystals in various organs and tissues. Cysteamine works by reacting with cystine to form a compound that can be more easily eliminated from the body. It is available in oral and topical forms and may also be used for other indications, such as treating lung diseases and radiation-induced damage.

'Escherichia coli (E. coli) proteins' refer to the various types of proteins that are produced and expressed by the bacterium Escherichia coli. These proteins play a critical role in the growth, development, and survival of the organism. They are involved in various cellular processes such as metabolism, DNA replication, transcription, translation, repair, and regulation.

E. coli is a gram-negative, facultative anaerobe that is commonly found in the intestines of warm-blooded organisms. It is widely used as a model organism in scientific research due to its well-studied genetics, rapid growth, and ability to be easily manipulated in the laboratory. As a result, many E. coli proteins have been identified, characterized, and studied in great detail.

Some examples of E. coli proteins include enzymes involved in carbohydrate metabolism such as lactase, sucrase, and maltose; proteins involved in DNA replication such as the polymerases, single-stranded binding proteins, and helicases; proteins involved in transcription such as RNA polymerase and sigma factors; proteins involved in translation such as ribosomal proteins, tRNAs, and aminoacyl-tRNA synthetases; and regulatory proteins such as global regulators, two-component systems, and transcription factors.

Understanding the structure, function, and regulation of E. coli proteins is essential for understanding the basic biology of this important organism, as well as for developing new strategies for combating bacterial infections and improving industrial processes involving bacteria.

A point mutation is a type of genetic mutation where a single nucleotide base (A, T, C, or G) in DNA is altered, deleted, or substituted with another nucleotide. Point mutations can have various effects on the organism, depending on the location of the mutation and whether it affects the function of any genes. Some point mutations may not have any noticeable effect, while others might lead to changes in the amino acids that make up proteins, potentially causing diseases or altering traits. Point mutations can occur spontaneously due to errors during DNA replication or be inherited from parents.

Leucine is an essential amino acid, meaning it cannot be produced by the human body and must be obtained through the diet. It is one of the three branched-chain amino acids (BCAAs), along with isoleucine and valine. Leucine is critical for protein synthesis and muscle growth, and it helps to regulate blood sugar levels, promote wound healing, and produce growth hormones.

Leucine is found in various food sources such as meat, dairy products, eggs, and certain plant-based proteins like soy and beans. It is also available as a dietary supplement for those looking to increase their intake for athletic performance or muscle recovery purposes. However, it's important to consult with a healthcare professional before starting any new supplement regimen.

The liver is a large, solid organ located in the upper right portion of the abdomen, beneath the diaphragm and above the stomach. It plays a vital role in several bodily functions, including:

1. Metabolism: The liver helps to metabolize carbohydrates, fats, and proteins from the food we eat into energy and nutrients that our bodies can use.
2. Detoxification: The liver detoxifies harmful substances in the body by breaking them down into less toxic forms or excreting them through bile.
3. Synthesis: The liver synthesizes important proteins, such as albumin and clotting factors, that are necessary for proper bodily function.
4. Storage: The liver stores glucose, vitamins, and minerals that can be released when the body needs them.
5. Bile production: The liver produces bile, a digestive juice that helps to break down fats in the small intestine.
6. Immune function: The liver plays a role in the immune system by filtering out bacteria and other harmful substances from the blood.

Overall, the liver is an essential organ that plays a critical role in maintaining overall health and well-being.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

S-Nitrosoglutathione (GSNO) is defined as a type of nitrosothiol, which is a class of compounds containing a nitroso (āˆ’NO) group attached to a sulfur atom. Specifically, GSNO is the result of the attachment of a nitric oxide (NO) molecule to the sulfur atom of the tripeptide glutathione (GSH). This compound has been the subject of extensive research due to its potential role in the regulation of various biological processes, including cell signaling, vasodilation, and neurotransmission, among others. It is also known to have antioxidant properties and to play a role in the immune response. However, it should be noted that abnormal levels of GSNO have been associated with various pathological conditions, such as cancer, neurodegenerative diseases, and cardiovascular disorders.

Molecular structure, in the context of biochemistry and molecular biology, refers to the arrangement and organization of atoms and chemical bonds within a molecule. It describes the three-dimensional layout of the constituent elements, including their spatial relationships, bond lengths, and angles. Understanding molecular structure is crucial for elucidating the functions and reactivities of biological macromolecules such as proteins, nucleic acids, lipids, and carbohydrates. Various experimental techniques, like X-ray crystallography, nuclear magnetic resonance (NMR) spectroscopy, and cryo-electron microscopy (cryo-EM), are employed to determine molecular structures at atomic resolution, providing valuable insights into their biological roles and potential therapeutic targets.

A chemical model is a simplified representation or description of a chemical system, based on the laws of chemistry and physics. It is used to explain and predict the behavior of chemicals and chemical reactions. Chemical models can take many forms, including mathematical equations, diagrams, and computer simulations. They are often used in research, education, and industry to understand complex chemical processes and develop new products and technologies.

For example, a chemical model might be used to describe the way that atoms and molecules interact in a particular reaction, or to predict the properties of a new material. Chemical models can also be used to study the behavior of chemicals at the molecular level, such as how they bind to each other or how they are affected by changes in temperature or pressure.

It is important to note that chemical models are simplifications of reality and may not always accurately represent every aspect of a chemical system. They should be used with caution and validated against experimental data whenever possible.

Glutathione disulfide (GSSG) is the oxidized form of glutathione (GSH), which is a tripeptide composed of three amino acids: cysteine, glutamic acid, and glycine. It plays a crucial role in maintaining cellular redox homeostasis by scavenging free radicals and reactive oxygen species (ROS) in the body.

Glutathione exists in two forms - reduced (GSH) and oxidized (GSSG). In the reduced form, glutathione has a sulfhydryl group (-SH), which can donate an electron to neutralize free radicals and ROS. When glutathione donates an electron, it becomes oxidized and forms glutathione disulfide (GSSG).

Glutathione disulfide is a dimer of two glutathione molecules linked by a disulfide bond (-S-S-) between the sulfur atoms of their cysteine residues. The body can recycle GSSG back to its reduced form (GSH) through the action of an enzyme called glutathione reductase, which requires NADPH as a reducing agent.

Maintaining a proper balance between GSH and GSSG is essential for cellular health, as it helps regulate various physiological processes such as DNA synthesis, gene expression, immune function, and apoptosis (programmed cell death). An imbalance in glutathione homeostasis can lead to oxidative stress, inflammation, and the development of various diseases.

Nitrosation is a chemical reaction that involves the addition of a nitrosonium ion (NO+) to another molecule. In the context of medicine, particularly in relation to gastroenterology and oncology, nitrosation is often discussed in terms of its potential role in the formation of carcinogenic N-nitroso compounds (NOCs).

These NOCs can be formed when nitrites (compounds containing a nitrite ion, NO2-) or nitrous acid (HNO2) react with secondary amines or other amino compounds under acidic conditions. This reaction can occur in the stomach after the ingestion of foods or beverages that contain both nitrites and amines, such as processed meats and certain alcoholic beverages.

The formation of NOCs has been associated with an increased risk of various types of cancer, including gastric and esophageal cancer. However, it's important to note that the relationship between nitrosation and cancer is complex and not fully understood, as other factors such as the presence of antioxidants in the diet can also influence the formation of NOCs.

Matrix-Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI-MS) is a type of mass spectrometry that is used to analyze large biomolecules such as proteins and peptides. In this technique, the sample is mixed with a matrix compound, which absorbs laser energy and helps to vaporize and ionize the analyte molecules.

The matrix-analyte mixture is then placed on a target plate and hit with a laser beam, causing the matrix and analyte molecules to desorb from the plate and become ionized. The ions are then accelerated through an electric field and into a mass analyzer, which separates them based on their mass-to-charge ratio.

The separated ions are then detected and recorded as a mass spectrum, which can be used to identify and quantify the analyte molecules present in the sample. MALDI-MS is particularly useful for the analysis of complex biological samples, such as tissue extracts or biological fluids, because it allows for the detection and identification of individual components within those mixtures.

Oxidative stress is defined as an imbalance between the production of reactive oxygen species (free radicals) and the body's ability to detoxify them or repair the damage they cause. This imbalance can lead to cellular damage, oxidation of proteins, lipids, and DNA, disruption of cellular functions, and activation of inflammatory responses. Prolonged or excessive oxidative stress has been linked to various health conditions, including cancer, cardiovascular diseases, neurodegenerative disorders, and aging-related diseases.

A plasmid is a small, circular, double-stranded DNA molecule that is separate from the chromosomal DNA of a bacterium or other organism. Plasmids are typically not essential for the survival of the organism, but they can confer beneficial traits such as antibiotic resistance or the ability to degrade certain types of pollutants.

Plasmids are capable of replicating independently of the chromosomal DNA and can be transferred between bacteria through a process called conjugation. They often contain genes that provide resistance to antibiotics, heavy metals, and other environmental stressors. Plasmids have also been engineered for use in molecular biology as cloning vectors, allowing scientists to replicate and manipulate specific DNA sequences.

Plasmids are important tools in genetic engineering and biotechnology because they can be easily manipulated and transferred between organisms. They have been used to produce vaccines, diagnostic tests, and genetically modified organisms (GMOs) for various applications, including agriculture, medicine, and industry.

Carrier proteins, also known as transport proteins, are a type of protein that facilitates the movement of molecules across cell membranes. They are responsible for the selective and active transport of ions, sugars, amino acids, and other molecules from one side of the membrane to the other, against their concentration gradient. This process requires energy, usually in the form of ATP (adenosine triphosphate).

Carrier proteins have a specific binding site for the molecule they transport, and undergo conformational changes upon binding, which allows them to move the molecule across the membrane. Once the molecule has been transported, the carrier protein returns to its original conformation, ready to bind and transport another molecule.

Carrier proteins play a crucial role in maintaining the balance of ions and other molecules inside and outside of cells, and are essential for many physiological processes, including nerve impulse transmission, muscle contraction, and nutrient uptake.

Sulfur compounds refer to chemical substances that contain sulfur atoms. Sulfur can form bonds with many other elements, including carbon, hydrogen, oxygen, and nitrogen, among others. As a result, there is a wide variety of sulfur compounds with different structures and properties. Some common examples of sulfur compounds include hydrogen sulfide (H2S), sulfur dioxide (SO2), and sulfonic acids (R-SO3H).

In the medical field, sulfur compounds have various applications. For instance, some are used as drugs or drug precursors, while others are used in the production of medical devices or as disinfectants. Sulfur-containing amino acids, such as methionine and cysteine, are essential components of proteins and play crucial roles in many biological processes.

However, some sulfur compounds can also be harmful to human health. For example, exposure to high levels of hydrogen sulfide or sulfur dioxide can cause respiratory problems, while certain organosulfur compounds found in crude oil and coal tar have been linked to an increased risk of cancer. Therefore, it is essential to handle and dispose of sulfur compounds properly to minimize potential health hazards.

Acylation is a medical and biological term that refers to the process of introducing an acyl group (-CO-) into a molecule. This process can occur naturally or it can be induced through chemical reactions. In the context of medicine and biology, acylation often occurs during post-translational modifications of proteins, where an acyl group is added to specific amino acid residues, altering the protein's function, stability, or localization.

An example of acylation in medicine is the administration of neuraminidase inhibitors, such as oseltamivir (Tamiflu), for the treatment and prevention of influenza. These drugs work by inhibiting the activity of the viral neuraminidase enzyme, which is essential for the release of newly formed virus particles from infected cells. Oseltamivir is administered orally as an ethyl ester prodrug, which is then hydrolyzed in the body to form the active acylated metabolite that inhibits the viral neuraminidase.

In summary, acylation is a vital process in medicine and biology, with implications for drug design, protein function, and post-translational modifications.

Enzyme stability refers to the ability of an enzyme to maintain its structure and function under various environmental conditions, such as temperature, pH, and the presence of denaturants or inhibitors. A stable enzyme retains its activity and conformation over time and across a range of conditions, making it more suitable for industrial and therapeutic applications.

Enzymes can be stabilized through various methods, including chemical modification, immobilization, and protein engineering. Understanding the factors that affect enzyme stability is crucial for optimizing their use in biotechnology, medicine, and research.

Cadmium is a toxic heavy metal that is a byproduct of the mining and smelting of zinc, lead, and copper. It has no taste or smell and can be found in small amounts in air, water, and soil. Cadmium can also be found in some foods, such as kidneys, liver, and shellfish.

Exposure to cadmium can cause a range of health effects, including kidney damage, lung disease, fragile bones, and cancer. Cadmium is classified as a known human carcinogen by the International Agency for Research on Cancer (IARC) and the National Toxicology Program (NTP).

Occupational exposure to cadmium can occur in industries that produce or use cadmium, such as battery manufacturing, metal plating, and pigment production. Workers in these industries may be exposed to cadmium through inhalation of cadmium-containing dusts or fumes, or through skin contact with cadmium-containing materials.

The general population can also be exposed to cadmium through the environment, such as by eating contaminated food or breathing secondhand smoke. Smoking is a major source of cadmium exposure for smokers and those exposed to secondhand smoke.

Prevention measures include reducing occupational exposure to cadmium, controlling emissions from industrial sources, and reducing the use of cadmium in consumer products. Regular monitoring of air, water, and soil for cadmium levels can also help identify potential sources of exposure and prevent health effects.

Carbon-oxygen lyases are a class of enzymes that catalyze the breaking of a carbon-oxygen bond using a molecule of water (H2O), resulting in the formation of an alcohol and a carbonyl group. These enzymes play important roles in various metabolic pathways, including the breakdown of carbohydrates, lipids, and amino acids.

The term "carbon-oxygen lyase" is used to describe enzymes that use a lytic cleavage mechanism to break a carbon-oxygen bond, as opposed to other types of enzymes that use oxidative or reductive mechanisms. These enzymes typically require the presence of cofactors such as metal ions or organic molecules to facilitate the reaction.

Carbon-oxygen lyases can be further classified based on the type of substrate they act upon and the specific reaction they catalyze. For example, some carbon-oxygen lyases are involved in the conversion of glyceraldehyde 3-phosphate to dihydroxyacetone phosphate during glycolysis, while others are involved in the breakdown of lignin, a complex polymer found in plant cell walls.

It's worth noting that carbon-oxygen lyases can also be classified as EC 4.2.1 under the Enzyme Commission (EC) numbering system, which provides a standardized nomenclature for enzymes based on the type of reaction they catalyze.

"Plant proteins" refer to the proteins that are derived from plant sources. These can include proteins from legumes such as beans, lentils, and peas, as well as proteins from grains like wheat, rice, and corn. Other sources of plant proteins include nuts, seeds, and vegetables.

Plant proteins are made up of individual amino acids, which are the building blocks of protein. While animal-based proteins typically contain all of the essential amino acids that the body needs to function properly, many plant-based proteins may be lacking in one or more of these essential amino acids. However, by consuming a variety of plant-based foods throughout the day, it is possible to get all of the essential amino acids that the body needs from plant sources alone.

Plant proteins are often lower in calories and saturated fat than animal proteins, making them a popular choice for those following a vegetarian or vegan diet, as well as those looking to maintain a healthy weight or reduce their risk of chronic diseases such as heart disease and cancer. Additionally, plant proteins have been shown to have a number of health benefits, including improving gut health, reducing inflammation, and supporting muscle growth and repair.

Protein engineering is a branch of molecular biology that involves the modification of proteins to achieve desired changes in their structure and function. This can be accomplished through various techniques, including site-directed mutagenesis, gene shuffling, directed evolution, and rational design. The goal of protein engineering may be to improve the stability, activity, specificity, or other properties of a protein for therapeutic, diagnostic, industrial, or research purposes. It is an interdisciplinary field that combines knowledge from genetics, biochemistry, structural biology, and computational modeling.

Cricetinae is a subfamily of rodents that includes hamsters, gerbils, and relatives. These small mammals are characterized by having short limbs, compact bodies, and cheek pouches for storing food. They are native to various parts of the world, particularly in Europe, Asia, and Africa. Some species are popular pets due to their small size, easy care, and friendly nature. In a medical context, understanding the biology and behavior of Cricetinae species can be important for individuals who keep them as pets or for researchers studying their physiology.

COS cells are a type of cell line that are commonly used in molecular biology and genetic research. The name "COS" is an acronym for "CV-1 in Origin," as these cells were originally derived from the African green monkey kidney cell line CV-1. COS cells have been modified through genetic engineering to express high levels of a protein called SV40 large T antigen, which allows them to efficiently take up and replicate exogenous DNA.

There are several different types of COS cells that are commonly used in research, including COS-1, COS-3, and COS-7 cells. These cells are widely used for the production of recombinant proteins, as well as for studies of gene expression, protein localization, and signal transduction.

It is important to note that while COS cells have been a valuable tool in scientific research, they are not without their limitations. For example, because they are derived from monkey kidney cells, there may be differences in the way that human genes are expressed or regulated in these cells compared to human cells. Additionally, because COS cells express SV40 large T antigen, they may have altered cell cycle regulation and other phenotypic changes that could affect experimental results. Therefore, it is important to carefully consider the choice of cell line when designing experiments and interpreting results.

The enzyme cysteine synthase, using sulfide sources, converts this ester into cysteine, releasing acetate. The cysteine ... Cysteine is encoded by the codons UGU and UGC. Like other amino acids (not as a residue of a protein), cysteine exists as a ... l-Cysteine is also used as a processing aid for baking. In the field of personal care, cysteine is used for permanent-wave ... N-Acetyl-l-cysteine is a derivative of cysteine wherein an acetyl group is attached to the nitrogen atom. This compound is sold ...
In human cysteine metabolism,[citation needed] L-cysteine is consumed in several ways as shown below. L-Cysteine is also ... L-Cysteine is the product of several processes as well. In addition to the reactions below, L-cysteine is also a product of ... Cysteine metabolism refers to the biological pathways that consume or create cysteine. The pathways of different amino acids ... D-cysteine desulfhydrase Sulfur metabolism (All articles with unsourced statements, Articles with unsourced statements from ...
In enzymology, a cysteine synthase (EC 2.5.1.47) is an enzyme that catalyzes the chemical reaction O3-acetyl-L-serine + ... Ikegami F, Kaneko M, Lambein F, Kuo Y-H, Murakoshi I (1987). "Difference between uracilylalanine synthases and cysteine ... This enzyme participates in 3 metabolic pathways: cysteine metabolism, selenoamino acid metabolism, and sulfur metabolism. It ... cysteine synthetase, S-sulfocysteine synthase, 3-O-acetyl-L-serine:hydrogen-sulfide, and 2-amino-2-carboxyethyltransferase. ...
In enzymology, a cysteine transaminase (EC 2.6.1.3) is an enzyme that catalyzes the chemical reaction L-cysteine + 2- ... Other names in common use include cysteine aminotransferase, L-cysteine aminotransferase, and CGT. This enzyme participates in ... The systematic name of this enzyme class is L-cysteine:2-oxoglutarate aminotransferase. ... the two substrates of this enzyme are L-cysteine and 2-oxoglutarate, whereas its two products are mercaptopyruvate and L- ...
The enzyme cysteine lyase (EC 4.4.1.10) catalyzes the chemical reaction L-cysteine + sulfite ā‡Œ {\displaystyle \ ... and L-cysteine hydrogen-sulfide-lyase (adding sulfite). This enzyme participates in cysteine and taurine metabolism. It employs ... Genes encoding cysteine lyase (CL) originated around 300 million years ago by a tandem gene duplication and ... The systematic name of this enzyme class is L-cysteine hydrogen-sulfide-lyase (adding sulfite; L-cysteate-forming). Other names ...
... (CDO) is a non-heme iron enzyme that catalyzes the conversion of L-cysteine to cysteine sulfinic acid ( ... cysteine sulfinate). CDO plays an important role in cysteine catabolism, regulating intracellular levels of cysteine and ... CDO is responsible for the first major step in metabolism of cysteine. CDO oxidizes to cysteine sulfinic acid (which exists ... Stipanuk MH, Dominy JE, Lee JI, Coloso RM (June 2006). "Mammalian cysteine metabolism: new insights into regulation of cysteine ...
In fact, the latex of dozens of different plant families are known to contain cysteine proteases. Cysteine proteases are used ... The MEROPS online database for peptidases and their inhibitors: Cysteine Peptidases Cysteine+endopeptidases at the U.S. ... Plant cysteine proteases isolated from these plants have been found to have high proteolytic activities that are known to ... Cysteine proteases are used as feed additives for livestock to improve the digestibility of proteins and amino acids. Protease ...
In enzymology, a cysteine desulfurase (EC 2.8.1.7) is an enzyme that catalyzes the chemical reaction L-cysteine + [enzyme]- ... The systematic name of this enzyme class is L-cysteine:[enzyme cysteine] sulfurtransferase. Other names in common use include ... the two substrates of this enzyme are L-cysteine and [enzyme]-cysteine], whereas its two products are L-alanine and [enzyme]-S- ... Zheng L, White RH, Cash VL, Jack RF, Dean DR (1993). "Cysteine desulfurase activity indicates a role for NIFS in metallocluster ...
This box: view edit Except where noted otherwise, data relate to Standard temperature and pressure. Reliability of data general note. ^a 52-90-4 (Articles with short description, Short description matches Wikidata, Chemical data pages, Chemical data pages cleanup ...
... s (also cysteine-rich peptide, CRP, disulphide-rich peptide) are small proteins that contain a large ... CRPs that form these typically have an even number of cysteines. Cysteines can coordinate one or more metal ions by forming a ... These cysteines either cross-link to form disulphide bonds, or bind metal ions by chelation, stabilising the protein's tertiary ... CRPs include a highly conserved secretion peptide signal at the N-terminus and a cysteine-rich region at the C-terminus. In an ...
L-cysteine ā‡Œ {\displaystyle \rightleftharpoons } NMP + diphosphate + N-[(R)-4'-phosphopantothenoyl]-L-cysteine The nucleoside ... Phosphopantothenate-cysteine ligase from the bacterium Escherichia coli uses cytidine triphosphate (CTP) as an energy donor, ... PDBe-KB provides an overview of all the structure information available in the PDB for Human Phosphopantothenate-cysteine ... In enzymology, a phosphopantothenate-cysteine ligase also known as phosphopantothenoylcysteine synthetase (PPCS) is an enzyme ( ...
... is derived from cysteine. Cysteine is formed from cystathionine via the cystathionine gamma-lyase enzyme ... Peptides containing the cysteine sulfinic acid residue are substrates for cysteine sulfinic acid reductase. ... by cysteine lyase or cystathionine gamma-lyase or enters the cysteine sulfinic acid pathway where it is oxidized by cysteine ... Cysteine sulfinic acid is the organic compound with the nominal formula HO2SCH2CH(NH2)CO2H . It is a rare example of an amino ...
L-cysteine + ATP ā‡Œ {\displaystyle \rightleftharpoons } Ī³-glutamyl cysteine + ADP + Pi GSH, and by extension GCL, is critical to ... Glutamate-cysteine ligase (GCL) EC 6.3.2.2), previously known as Ī³-glutamylcysteine synthetase (GCS), is the first enzyme of ... The plant glutamate cysteine ligase is a redox-sensitive homodimeric enzyme, conserved in the plant kingdom. In an oxidizing ... Animal glutamate cysteine ligase (GCL) is a heterodimeric enzyme composed of two protein subunits that are coded by independent ...
In enzymology, a cysteine-tRNA ligase (EC 6.1.1.16) is an enzyme that catalyzes the chemical reaction ATP + L-cysteine + ... and cysteine translase. This enzyme participates in cysteine metabolism and aminoacyl-trna biosynthesis. As of late 2007, 3 ... The systematic name of this enzyme class is L-cysteine:tRNACys ligase (AMP-forming). Other names in common use include ... L-cysteine, and tRNA(Cys), whereas its 3 products are AMP, diphosphate, and L-cysteinyl-tRNA(Cys). This enzyme belongs to the ...
A white solid, it is the methyl ester of the amino acid cysteine. Under the brand name Mecysteine, cysteine methyl ester is a ... Cysteine methyl ester is also used as a building block for synthesis of N,S-heterocycles. Page CP (2018). "Respiratory System: ... Cysteine methyl ester is the organic compound with the formula HSCH2CH(NH2)CO2CH3. ...
Other names in common use include cysteine conjugate aminotransferase, and cysteine-conjugate alpha-ketoglutarate transaminase ... In enzymology, a cysteine-conjugate transaminase (EC 2.6.1.75) is an enzyme that catalyzes the chemical reaction S-(4- ... The systematic name of this enzyme class is S-(4-bromophenyl)-L-cysteine:2-oxoglutarate aminotransferase. ... L-cysteine and 2-oxoglutarate, whereas its two products are S-(4-bromophenyl)mercaptopyruvate and L-glutamate. This enzyme ...
The enzyme D-cysteine desulfhydrase (EC 4.4.1.15) catalyzes the chemical reaction D-cysteine + H2O ā‡Œ {\displaystyle \ ... Schmidt A; Erdle I (1983). "A cysteine desulfhydrase specific for D-cysteine from the green-alga Chlorella fusca". Z. ... Schmidt A (1982). "A cysteine desulfhydrase from spinach leaves specific for D-cysteine". Z. Pflanzenphysiol. 107: 301-312. ... and D-cysteine sulfide-lyase (deaminating). This enzyme participates in cysteine metabolism. Nagasawa T, Ishii T, Kumagai H, ...
"Crystal structure of the cysteine-rich secretory protein stecrisp reveals that the cysteine-rich domain has a K+ channel ... Cysteine-rich secretory proteins, often abbreviated as CRISPs, are a group of glycoproteins. They are a subgroup of the CRISP, ... The primary structure is also rich in cysteine that form disulfide bonds, particularly in the hinge region and CRD. CRISPs are ... The larger domain is a CAP-like 'Pathogenesis-related 1' domain (PR-1), followed by the smaller ShK-like 'Cysteine-Rich Domain ...
... is a protein that in humans is encoded by the CRIP3 gene. GRCh38: Ensembl release 89: ENSG00000146215 ... "Entrez Gene: Cysteine rich protein 3". Retrieved 2018-01-02. v t e (Articles with short description, Short description matches ...
Dominy JE, Hwang J, Stipanuk MH (2007). "Overexpression of cysteine dioxygenase reduces intracellular cysteine and glutathione ... Cysteine dioxygenase type 1 is a protein that in humans is encoded by the CDO1 gene. GRCh38: Ensembl release 89: ... PDBe-KB provides an overview of all the structure information available in the PDB for Human Cysteine dioxygenase type 1 PDBe- ... KB provides an overview of all the structure information available in the PDB for Mouse Cysteine dioxygenase type 1 v t e ( ...
... , also known as thialysine, is a toxic analog of the amino acid lysine in which the second carbon of the ... Strictly speaking, L-thialysine is actually considered an S-(2-aminoethyl) analogue of L-cysteine. This compound is known to ... "S-(2-Aminoethyl)-L-cysteine". pubchem.ncbi.nlm.nih.gov. Retrieved 5 February 2023. H-Cys(aminoethyl)-OHĀ·HCl at ChemImpex ...
... may refer to: Protein geranylgeranyltransferase type I Protein ...
The enzyme cysteine-S-conjugate Ī²-lyase (EC 4.4.1.13) catalyzes the chemical reaction an L-cysteine-S-conjugate + H2O = a thiol ... glutamine transaminase K/cysteine conjugate Ī²-lyase, and L-cysteine-S-conjugate thiol-lyase (deaminating). It employs one ... Tateishi M, Suzuki S, Shimizu H (1978). "Cysteine conjugate Ī²-lyase in rat liver. A novel enzyme catalyzing formation of thiol- ... The systematic name of this enzyme class is L-cysteine-S-conjugate thiol-lyase (deaminating; pyruvate-forming). Other names in ...
... an S-substituted N-acetyl-L-cysteine Thus, the two substrates of this enzyme are acetyl-CoA and S-substituted L-cysteine, ... In enzymology, a cysteine-S-conjugate N-acetyltransferase (EC 2.3.1.80) is an enzyme that catalyzes the chemical reaction ... The systematic name of this enzyme class is acetyl-CoA:S-substituted L-cysteine N-acetyltransferase. This enzyme participates ... Duffel MW, Jakoby WB (1982). "Cysteine S-conjugate N-acetyltransferase from rat kidney microsomes". Mol. Pharmacol. 21 (2): 444 ...
The CAP superfamily (cysteine-rich secretory proteins, antigen 5, and pathogenesis-related 1 proteins (CAP)) is a large ... Many of these proteins contain a C-terminal Cysteine-rich secretory protein (Crisp) domain. This domain is found in the ... It contains 10 conserved cysteines which are all involved in disulphide bonds and is structurally related to the ion channel ... Gibbs GM, Scanlon MJ, Swarbrick J, Curtis S, Gallant E, Dulhunty AF, O'Bryan MK (February 2006). "The cysteine-rich secretory ...
It has a relatively unusual Ī³-bond between the constituent amino acids, L-glutamic acid and L-cysteine and is a key ... Mice that have had the glutamate-cysteine ligase (GCL) gene knocked out do not develop beyond the embryo stage and die before ... GGC is synthesized from L-glutamic acid and L-cysteine in the cytoplasm of virtually all cells in an adenosine triphosphate ( ... Ī³-L-Glutamyl-L-cysteine, also known as Ī³-glutamylcysteine (GGC), is a dipeptide found in animals, plants, fungi, some bacteria ...
In molecular biology, the protein domain SRCR is short for Scavenger receptor cysteine-rich domain. They are found solely in ... Hohenester E; Sasaki T; Timpl R (1999). "Crystal structure of a scavenger receptor cysteine-rich domain sheds light on an ... 2011). "A novel scavenger receptor-cysteine-rich (SRCR) domain containing scavenger receptor identified from mollusk mediated ...
... may refer to: S-alkylcysteine lyase, an enzyme Alliinase, an enzyme This disambiguation page ... lists articles associated with the title S-alkyl-L-cysteine sulfoxide lyase. If an internal link led you here, you may wish to ...
... protein S-methyl-L-cysteine Thus, the two substrates of this enzyme are DNA containing 6-O-methylguanine and protein L-cysteine ... whereas its two products are DNA and protein S-methyl-L-cysteine. The S-methyl-L-cysteine residue irreversibly inactivates the ... The systematic name of this enzyme class is DNA-6-O-methylguanine:[protein]-L-cysteine S-methyltransferase. As of late 2007, 11 ... In enzymology, a methylated-DNA-[protein]-cysteine S-methyltransferase (EC 2.1.1.63) is an enzyme that catalyzes the chemical ...
... is a protein that in humans is encoded by the CRISPLD1 gene. GRCh38: ... "Entrez Gene: Cysteine rich secretory protein LCCL domain containing 1". Retrieved 2017-01-26. v t e (Articles with short ...
The enzyme cysteine synthase, using sulfide sources, converts this ester into cysteine, releasing acetate. The cysteine ... Cysteine is encoded by the codons UGU and UGC. Like other amino acids (not as a residue of a protein), cysteine exists as a ... l-Cysteine is also used as a processing aid for baking. In the field of personal care, cysteine is used for permanent-wave ... N-Acetyl-l-cysteine is a derivative of cysteine wherein an acetyl group is attached to the nitrogen atom. This compound is sold ...
... comes from the amino acid L-cysteine. It has many uses, and is available as both a prescription drug and a dietary supplement. ... Allergy: Dont use N-acetyl cysteine if you are allergic to acetyl cysteine.. Asthma: N-acetyl cysteine might cause ... Taking N-acetyl cysteine by mouth seems to reduce flu symptoms.. *Kidney failure. Taking N-acetyl cysteine by mouth seems to ... N-acetyl cysteine (NAC) comes from the amino acid L-cysteine. Amino acids are building blocks of proteins. NAC has many uses ...
Endometrioma and N-Acetyl Cysteine - Infertility at BellaOnline ... N-acetyl cysteine may be able to shrink or resolve ... and an Italian study published in 2013 discovered that N-acetyl cysteine (NAC) may be particularly a effective endometrioma ...
Synonyms: <I>N</I>-Acetyl-<SC>L</SC>-cysteine, LNAC, NAC. CAS 616-91-1. Molecular Weight 163.19. Browse ...
CSRNP_N; Cysteine/serine-rich nuclear protein N-terminus. * NM_178634.2 ā†’ NP_848749.2 cysteine/serine-rich nuclear protein 3 ... CSRNP_N; Cysteine/serine-rich nuclear protein N-terminus. * NM_001290666.1 ā†’ NP_001277595.1 cysteine/serine-rich nuclear ... CSRNP_N; Cysteine/serine-rich nuclear protein N-terminus. * XM_030252234.1 ā†’ XP_030108094.1 cysteine/serine-rich nuclear ... CSRNP_N; Cysteine/serine-rich nuclear protein N-terminus. * XM_030252235.1 ā†’ XP_030108095.1 cysteine/serine-rich nuclear ...
1994) Cysteine string proteins-a potential link between synaptic vesicles and presynaptic Ca2+ channels. Science 263:981-982. ... 1990) A cysteine-string protein is expressed in retina and brain of Drosophila. J Neurogenet 7:15-29. ... 1998) Cysteine-string proteins regulate exocytosis of insulin independent from transmembrane ion fluxes. FEBS Lett 437:267-272. ... 1998) Cysteine string protein (CSP) is an insulin secretory granule-associated protein regulating beta-cell exocytosis. EMBO J ...
Reversible cysteine modifications allow for potential redox regulation of proteins. Traditional measurement of the relative ... Our method allows for the identification of the proteins, identification of redox-sensitive cysteines within proteins, and ... Cysteines are one of the most rarely used amino acids, but when conserved in proteins they often play critical roles in ... of iTRAQ reagents in combination with a previous thiol selection method to relatively quantify the redox state of cysteines ...
Protein target information for Cysteine desulfurase IscS ([Haemophilus] ducreyi 35000HP). Find diseases associated with this ...
... but some people can further benefit from additional cysteine sources, such as through supplements and food. Learn more! ... Cysteines are amino acids produced naturally by the body, ... The difference between L-cysteines and D-cysteines Cysteines ... The uses of L-cysteines As discussed, common applications for L-cysteine are as a dough conditioner and preservative , among ... L-cysteine is a common food additive. D-cysteine, on the other hand, is not an additive in food or flavoring agents. It is more ...
L-Cysteine Mono HCI Powder L-Cysteine is a sulfur-containing amino acid that is converted in the body to N-acetyl cysteine, a ... Cysteine (as L-Cysteine monohydrochloride monohydrate) 900 mg Warning: If you are pregnant or breastfeeding, consult your ... Cysteine is also a part of the reduced glutathione molecule, which plays an important role in the livers detoxification ... Source Naturals L-Cysteine powders are HYPOALLERGENIC: contains no yeast, dairy, egg, gluten, corn, soy or wheat. Contains no ...
Shop for Country Life NAC N-Acetyl Cysteine 750 mg Vegetarian Capsules (30 ct) at Fred Meyer. Find quality health products to ... N-acetyl cysteine (NAC) supports both liver health and lung health. NAC acts as an antioxidant by scavenging harmful free ... Country Life NAC N-Acetyl Cysteine 750 mg Vegetarian Capsules. 30 ctUPC: 0001579401686 ... radicals and is a cysteine precursor to the antioxidant, glutathione. As part of the cellular antioxidant defense system, ...
Weil answers a readerļæ½s question about N-acetyl-L-cysteine and possible NAC side effects when used to treat OCD. ... NAC or N-acetyl L-cysteine for OCD?. Have you been following the studies on the use of NAC for obsessive-compulsive disorder ( ... NAC (N-acetylcysteine) is a modified form of the amino acid cysteine that helps the body synthesize glutathione, an important ... Animal studies at the Medical University of South Carolina have found that N-acetly-cysteine can lower levels of brain ...
L-Cysteine. D00026 L-Cysteine (JP18). Drugs listed in the Japanese Pharmacopoeia [BR:br08311]. Chemicals. D00026 L-Cysteine. ... D00026 L-Cysteine (JP18). Risk category of Japanese OTC drugs [BR:br08312]. Third-class OTC drugs. Inorganic and organic ... D00026 L-Cysteine (JP18). Classification of Japanese OTC drugs [BR:br08313]. Nourishing tonics and health supplements. 45 ...
Product Description Package Description: 60 Capsules x 600mgAn effective way to support healthy antioxidant glutathione levels*. Oral glutathione is not absorbed well. Glutathione is one of our two basic antioxidant enzymes along with S.O.D. These import
Underground Labs NAC (N-Acetyl-Cysteine) is the supplement form of the semi-essential amino acid cysteine. Its considered semi ... N-Acetyl-Cysteine) is the supplement form of the semi-essential amino acid cysteine. It’s considered semi-essential ... N-Acetyl-Cysteine) is the supplement form of the semi-essential amino acid cysteine. It’s considered semi-essential ... Cysteine is found in most high-protein foods, such as chicken, turkey, yogurt, cheese, eggs, sunflower seeds and legumes. ...
... containing N-Acetyl-L-Cysteine, an amino acid. ... NAC (N-Acetyl Cysteine) 600mg 60caps (Solgar). Rated 0 out of 5 ... Ingredients: N-Acetyl Cysteine (free form). Warning: if you are pregnant, nursing, taking any medications or have any medical ... NAC 600 mg is one of Solgars premium-quality amino acid range products, containing N-Acetyl-L-Cysteine, an amino acid. ...
S-(N-benzylpyrrol-2-yl)cysteine ,S-(2-pyrrolyl)cysteine,S-(N-methylpyrrol-2-yl)cysteine ... Synthesis of cysteine sulfoxides and related compounds occurring in wild onions Cysteine sulfoxides are important secondary ... Part I: Cysteine Sulfoxides of Flowers. Part 2: Anticancer Activity of Bulb Extracts. by: Jivishov, Emil Published: (2018) ... Different types of cysteine sulfoxides have been identified in many of Allium species, of which methiin, alliin, propiin, ...
The Parkinsons disease protein DJ-1 is neuroprotective due to cysteine-sulfinic acid-driven mitochondrial localization. Proc ...
N-Acetyl-L-Cysteine) - Free Radical Protection, Helps Support Liver FunctionHelps Your Bodys Detoxification System, Supports ... Allmax Nutrition NAC (N-Acetyl-L-Cysteine). Allmax Nutrition NAC (N-Acetyl-L-Cysteine) ... Decrease quantity for Allmax Nutrition NAC (N-Acetyl-L-Cysteine) Increase quantity for Allmax Nutrition NAC (N-Acetyl-L- ... Home ā€ŗProducts ā€ŗ Allmax Nutrition NAC (N-Acetyl-L-Cysteine) .section-template--19986027675954__main-padding { padding-top: 27px ...
Proposed Amino Acid Sequence and the 1.63 Angstrom X-ray Crystal Structure of a Plant Cysteine Protease Ervatamin B: Insight ... Proposed amino acid sequence and the 1.63 A X-ray crystal structure of a plant cysteine protease, ervatamin B: Some insights ... Proposed Amino Acid Sequence and the 1.63 Angstrom X-ray Crystal Structure of a Plant Cysteine Protease Ervatamin B: Insight ... The crystal structure of a cysteine protease ervatamin B, isolated from the medicinal plant Ervatamia coronaria, has been ...
These results suggest that cysteine P may be activated in the rat stomach after E or A exposure, and cysteine P may have a role ... Role of cysteine proteases and protease inhibitors in gastric mucosal damage induced by ethanol or ammonia in the rat.. ... Role of cysteine proteases and protease inhibitors in gastric mucosal damage induced by ethanol or ammonia in the rat.. ... Mucosal presence and activity of cysteine PI and cathepsin B have also been investigated in the pathogenesis of chemically ...
Functional characterization of the alanine-serine-cysteine exchanger of Carnobacterium sp AT7 ...
L-cysteine [ACD/IUPAC Name] N-Acetyl-S-(3-methy. l-1,4-dioxo-1,4-dih. ydro-2-naphthalinyl. )-L-cystein [German] [ACD/IUPAC Name ... L-Cysteine, N-acety. l-S-(1,4-dihydro-3-. methyl-1,4-dioxo-2-. naphthalenyl)- [ACD/Index Name] ...
N-Acetyl L-Cysteine) (120 VeggieCaps). Relieves chronic bronchitis symptoms. Promotes respiratory health. Protects liver. ... N-Acetyl-L-Cysteine, or N-A-C, is an acetylated form of the amino acid cysteine. Cysteine is the most important precursor to ... Acetylated cysteine is better absorbed than regular cysteine. AORs N-A-C is an excellent choice for those looking for a single ... NAC 500mg (N-Acetyl L-Cysteine) (240 VeggieCaps) AOR. CAD $57.67. Related products. * L-Tyrosine 500mg (60 Capsules) ** size ...
Recombinant Human Sperm mitochondrial-associated cysteine-rich protein (SMCP) from Cusabio. Cat Number: CSB-EP021820HU. USA, UK ... Recombinant Human Sperm mitochondrial-associated cysteine-rich protein (SMCP) , CSB-EP021820HU. (No reviews yet) Write a Review ... Sperm mitochondria associated cysteine rich protein; Sperm mitochondrial-associated cysteine-rich protein ... Recombinant Human Sperm mitochondrial-associated cysteine-rich protein (SMCP) , CSB-EP021820HU Cusabio Human Recombinants ...
... is a stable form of the amino acid L-Cysteine and is an effective way to boost Glutathione levels in the body. ... Decrease quantity for N-Acetyl Cysteine (NAC) Increase quantity for N-Acetyl Cysteine (NAC) ... N-acetyl-l-cysteine-commonly referred to as NAC -is a stable form of the amino acid cysteine. It provides antioxidant support, ... N-Acetyl L-Cysteine 500 mg. Other ingredients: Capsule (cellulose), microcrystalline cellulose, silica, magnesium stearate. ...
N-Acetyl-L-Cysteine (NAC) is an amino acid that aids in the production of this essential antioxidantā€š making it a sought-after ... N-Acetyl Cysteineā„¢ helps support:. ā€¢ Healthy liver function. ā€¢ Optimal detoxification. ā€¢ Antioxidant maintenance. ā€¢ Healthy ... Designs for Health N-Acetyl-Cysteine (NAC) - 120 Vegetarian Capsules Shop all Designs for Health products ...
L-Cysteine is an easily-absorbed nutrient with strong benefits for bronchial, respiratory and liver health. ... N-Acetyl-L-Cysteine supplements (NAC supplements) are among Life Extension best sellers. ... N-acetyl-L-cysteine is an easily-absorbed nutrient with potent benefits for whole body health.1 N-acetyl-L-cysteine also helps ... What Is N-Acetyl-L-Cysteine?. As a dietary supplement, N-acetyl-L-cysteine supports comprehensive health in a variety of ways, ...
Alizadeh, B., Salehzadeh, A., Ranji, N. et al. Effects of N-Acetyl Cysteine on Genes Expression of c-myc, and Ask-1, ... Effects of N-Acetyl Cysteine on Genes Expression of c-myc, and Ask-1, Histopathological, Oxidative Stress, Inflammation, and ... Chen S, Ren Q, Zhang J, Ye Y, Zhang Z, Xu Y, Chen L (2014) N-acetyl-L-cysteine protects against cadmium-induced neuronal ...
Cysteine containing dipeptides were not associated with metal affinities that followed the Irving-Williams se Celebrating our ... Cysteine containing dipeptides show a metal specificity that matches the composition of seawater L. Belmonte, D. Rossetto, M. ... Cysteine containing dipeptides show a metal specificity that matches the composition of seawaterā€  ... Cysteine containing dipeptides were not associated with metal affinities that followed the Irving-Williams series but did ...
  • Due to the ability of thiols to undergo redox reactions, cysteine and cysteinyl residues have antioxidant properties. (wikipedia.org)
  • N-acetyl cysteine is an antioxidant that might play a role in preventing cancer. (medlineplus.gov)
  • L-Cysteine is a sulfur-containing amino acid that is converted in the body to N-acetyl cysteine, a potent antioxidant. (vitasprings.com)
  • NAC acts as an antioxidant by scavenging harmful free radicals and is a cysteine precursor to the antioxidant, glutathione. (fredmeyer.com)
  • NAC (N-acetylcysteine) is a modified form of the amino acid cysteine that helps the body synthesize glutathione, an important antioxidant. (drweil.com)
  • Cysteine is the most important precursor to glutathione (GSH), the most critical antioxidant produced in the body. (feelgoodnatural.com)
  • N-acetyl-L-cysteine is a powerful antioxidant that protects your cells from oxidative stress. (lifeextension.com)
  • Nā€‘acetyl cysteine (NAC) has been shown to exhibit antioxidant effects in vitro. (spandidos-publications.com)
  • The body makes this into cysteine that supports a healthy balance of the powerful antioxidant, glutathione. (nutritionexpress.com)
  • Cysteine is a key component of the antioxidant glutathione. (organicfoodsandcafe.com)
  • The reactivity is enhanced when the thiol is ionized, and cysteine residues in proteins have pKa values close to neutrality, so are often in their reactive thiolate form in the cell. (wikipedia.org)
  • This study was focused on the dynamic regulation of the activity of plant GSNORs through reversible S-nitrosation and/or oxidative modifications of target cysteine residues. (muni.cz)
  • Previous studies using rat renal brush-border membrane vesicles indicated that cysteine and histidine residues played critical roles in H + /organic cation antiport activity. (aspetjournals.org)
  • In the present study, essential histidine and cysteine residues of MATE1 family were elucidated. (aspetjournals.org)
  • When 7 histidine and 12 cysteine residues of rat (r)MATE1 conserved among species were mutated, substitution of His-385, Cys-62, and Cys-126 led to a significant loss of tetraethylammonium (TEA) transport activity. (aspetjournals.org)
  • The PCMBS-caused inhibition of the transport via rMATE1 was protected by an excess of various organic cations such as TEA, suggesting that cysteine residues act as substrate-binding sites. (aspetjournals.org)
  • These results suggest that histidine and cysteine residues are required for MATE1 to function and that cysteine residues may serve as substrate-recognition sites. (aspetjournals.org)
  • Cleavage of the target peptide from the resin is performed using carboxymethylsulfenyl chloride under mild conditions which gave in situ thiol-sulfenyl protection of the cysteine residues. (eurekamag.com)
  • Like other amino acids (not as a residue of a protein), cysteine exists as a zwitterion. (wikipedia.org)
  • In high-protein diets, cysteine may be partially responsible for reduced blood pressure and stroke risk. (wikipedia.org)
  • Orthologous to human CSRNP3 (cysteine and serine rich nuclear protein 3). (nih.gov)
  • Within an individual protein there may be a number of cysteines which could allow for multiple thiol modifications. (hindawi.com)
  • Cysteines often form part of active sites, allowing for the protein to be switched on or off depending on redox state. (hindawi.com)
  • Interactions with other proteins or molecules are another feature of cysteines that can affect protein activity. (hindawi.com)
  • Thus, reversible cysteine modifications can influence protein activity and the relative quantification of the status of the thiol can potentially provide valuable insights into protein activity where the protein exists in a range of redox states. (hindawi.com)
  • Previous studies suggest that the vesicular cysteine-string protein (CSP) may modulate presynaptic Ca 2+ channel activity in fast neurotransmitter release. (jneurosci.org)
  • The Parkinson's disease protein DJ-1 is neuroprotective due to cysteine-sulfinic acid-driven mitochondrial localization. (alzforum.org)
  • Canet-AvilĆ©s RM, Wilson MA, Miller DW, Ahmad R, McLendon C, Bandyopadhyay S, Baptista MJ, Ringe D, Petsko GA, Cookson MR . The Parkinson's disease protein DJ-1 is neuroprotective due to cysteine-sulfinic acid-driven mitochondrial localization . (alzforum.org)
  • 2sigma(F). The protein belongs to the papain superfamily of cysteine proteases and has some unique properties compared to other members of the family. (rcsb.org)
  • In humans, the cysteine-containing tripeptide glutathione (GSH) is an essential thiol cofactor that maintains an intracellular reducing environment to protect against oxidative stress, which causes lipid, protein & DNA damage. (findaphd.com)
  • Cysteine is a non-essential sulfur amino acid, which is found in most high-protein foods such as dairy, meat, and legumes. (nutritionexpress.com)
  • Using a rat model of CIH-HTN, we investigated the impact of short-term (1 and 7 days), mid-term (14 and 21 days, pre-HTN), and long-term intermittent hypoxia (IH) (up to 60 days, established HTN) on Cyp1a1 protein level (a sensitive hallmark of AhR activation) and cysteine-related thiol pools. (unl.pt)
  • While short-term IH decreased Cyp1a1 and increased protein-S-thiolation, long-term IH increased Cyp1a1 and free oxidized cysteine. (unl.pt)
  • so it must be biosynthesized from its constituent amino acids, cysteine, glycine, and glutamic acid. (wikipedia.org)
  • Cysteines are one of the most rarely used amino acids, but when conserved in proteins they often play critical roles in structure, function, or regulation. (hindawi.com)
  • Cysteines are amino acids produced naturally by the body, but some people can further benefit from additional cysteine sources, such as through supplements and food. (brenntag.com)
  • Role of cysteine proteases and protease inhibitors in gastric mucosal damage induced by ethanol or ammonia in the rat. (jci.org)
  • MG-101 (ALLN) is a cell-permeable and potent inhibitor of cysteine proteases including calpains and lysosomal cathepsins. (adooq.com)
  • In plants and bacteria, cysteine biosynthesis also starts from serine, which is converted to O-acetylserine by the enzyme serine transacetylase. (wikipedia.org)
  • Characterization of a family of novel cysteine- serine-rich nuclear proteins (CSRNP). (nih.gov)
  • Cysteine synthesizes from serine, which synthesizes from phosphoglycerates that form during glycolysis. (brenntag.com)
  • The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. (wikipedia.org)
  • We propose application of iTRAQ reagents in combination with a previous thiol selection method to relatively quantify the redox state of cysteines both within and between samples in a single analysis. (hindawi.com)
  • Allosterically regulated proteins that require an activator are sometimes based on a thiol exchange interaction involving cysteines, for example, pyruvate kinase uses fructose bisphosphate (FBPs) as a heterotrophic activator and it contains a cysteine in its FBP binding site [ 8 ]. (hindawi.com)
  • N-acetyl cysteine (NAC) comes from the amino acid L-cysteine. (medlineplus.gov)
  • People commonly use N-acetyl cysteine for cough and other lung conditions. (medlineplus.gov)
  • There is also no good evidence to support using N-acetyl cysteine for COVID-19. (medlineplus.gov)
  • Although many dietary supplement products contain N-acetyl cysteine, the US FDA has stated that it's illegal for dietary supplements to contain N-acetyl cysteine since it's technically an approved drug. (medlineplus.gov)
  • It may allow for N-acetyl cysteine in dietary supplements as long as no safety issues come up. (medlineplus.gov)
  • Prescription N-acetyl cysteine products are available under the guidance of a healthcare provider. (medlineplus.gov)
  • Taking prescription N-acetyl cysteine by mouth or by IV reduces the death rate and prevents permanent harm caused by acetaminophen poisoning. (medlineplus.gov)
  • Inhaling a prescription form of N-acetyl cysteine helps treat collapsed lungs caused by mucus blockage. (medlineplus.gov)
  • Inhaling a prescription form of N-acetyl cysteine is helpful to prepare people for diagnostic lung tests. (medlineplus.gov)
  • Inhaling a prescription form of N-acetyl cysteine helps prevent crusting in people with a tube in the windpipe. (medlineplus.gov)
  • Taking N-acetyl cysteine by mouth or by IV seems to improve chest pain when used with the drug nitroglycerin. (medlineplus.gov)
  • Taking N-acetyl cysteine by IV also seems to help prevent nitroglycerin tolerance, but it might increase the risk for headaches and low blood pressure. (medlineplus.gov)
  • Taking N-acetyl cysteine by mouth might improve irritability in children and adolescents with autism. (medlineplus.gov)
  • Taking N-acetyl cysteine by mouth seems to reduce shortness of breath and coughing from this condition. (medlineplus.gov)
  • Also, taking N-acetyl cysteine by mouth for 3-36 months seems to prevent flare-ups. (medlineplus.gov)
  • Taking N-acetyl cysteine by mouth for at least 6 months seems to decrease flare-ups by about 40% in people with moderate to severe COPD. (medlineplus.gov)
  • In people with COPD who need to be hospitalized, taking N-acetyl cysteine in addition to regular treatment helps with recovery. (medlineplus.gov)
  • Taking N-acetyl cysteine by mouth, with or without other drugs, might help to prevent kidney problems caused by dyes used during some X-ray exams. (medlineplus.gov)
  • Taking N-acetyl cysteine by mouth seems to reduce homocysteine levels, a possible risk factor for heart disease. (medlineplus.gov)
  • Taking N-acetyl cysteine by mouth seems to reduce levels of a blood fat called lipoprotein(a) in people with high levels of this blood fat. (medlineplus.gov)
  • A little-known fertility fact is that endometriomas are thought to be sensitive to modulation via select antioxidants, and an Italian study published in 2013 discovered that N-acetyl cysteine (NAC) may be particularly a effective endometrioma treatment strategy which does not interfere negatively with fertility, also, prior studies in animals have demonstrated a remarkable ability to curb the growth and spread of endometriosis. (bellaonline.com)
  • N-acetyl cysteine (NAC) supports both liver health and lung health. (fredmeyer.com)
  • https://www.mrsupplement.com.au/underground-labs-nac?variation=15029 Underground Labs NAC (180 Capsules / 180 Serves) Underground Labs NAC (N-Acetyl-Cysteine) is the supplement form of the semi-essential amino acid cysteine. (mrsupplement.com.au)
  • Underground Labs NAC (N-Acetyl-Cysteine) is the supplement form of the semi-essential amino acid cysteine. (mrsupplement.com.au)
  • At the time of writing NAC (N Acetyl Cysteine) is NOT banned. (mrsupplement.com.au)
  • N-acetyl cysteine is a more stable form of the sulfur amino acid L-cysteine, and is a powerful cysteine and glutathione precursor. (vitanetonline.com)
  • Additionally, a meta-analysis of human clinical trials has reported that N-acetyl cysteine supplementation supports respiratory health. (vitanetonline.com)
  • To determine if N-acetyl-cysteine (NAC) could be associated with lower mortality risk. (ersjournals.com)
  • N-acetyl cysteine (NAC) is a stable form of the non-essential amino acid cysteine. (hihealth.com)
  • FREE RADICAL PROTECTION*/NORMAL IMMUNE SYSTEM FUNCTION*: N-acetyl cysteine (NAC) is a stable form of the non-essential amino acid cysteine. (hihealth.com)
  • N-acetyl cysteine (NAC) provides a high potency dose of the sulphur amino acid, cysteine. (organicfoodsandcafe.com)
  • Effective - Provides 1500mg of N-acetyl cysteine per daily intake in a highly absorbable form that can easily be used by the body. (organicfoodsandcafe.com)
  • N-Acetyl Cysteine, Capsule Shell (Hydroxypropyl Methylcellulose), Anti-Caking Agents (Silicon Dioxide & Magnesium Stearate). (organicfoodsandcafe.com)
  • Reversible cysteine modifications allow for potential redox regulation of proteins. (hindawi.com)
  • Our method allows for the identification of the proteins, identification of redox-sensitive cysteines within proteins, and quantification of the redox status of individual cysteine-containing peptides. (hindawi.com)
  • Cysteine is the most important redox-responsive amino acid within proteins largely due to the wide range of oxidation states that sulfur can occupy-so called, "sulfur switches" [ 4 ]. (hindawi.com)
  • Oral NAC (or N-Acetyl-L-Cysteine) supplements encourage healthy glutathione levels-so you can stay at your best. (lifeextension.com)
  • Supplement with N-Acetyl-L-Cysteine to promote healthy glutathione levels. (lifeextension.com)
  • N-Acetyl-L-Cysteine (NAC) is a more stable form of the amino acid L-Cysteine and is the most effective way to boost Glutathione levels in the body. (nutrabio.com)
  • Alteration of intracellular cysteine and glutathione levels in alveolar macrophages and lymphocytes by diesel exhaust particle exposure. (cdc.gov)
  • Bluebonnet s L-Cysteine 500 mg Vcaps provide free-form L-cysteine in easy-to-swallow vegetable capsules for maximum assimilation and absorption. (nourishingfoods.com)
  • NAC by Seeking Health provides 500 mg of N-acetyl-L-cysteine (NAC) per vegetarian capsule. (healthrangerstore.com)
  • Cysteine can usually be synthesized by the human body under normal physiological conditions if a sufficient quantity of methionine is available. (wikipedia.org)
  • When used as a food additive, cysteine has the E number E920. (wikipedia.org)
  • L-cysteine is a common food additive. (brenntag.com)
  • Wacker-Chemie said in August that it had produced the amino acid L-cysteine from dextrose, by fermentation, at its Munich site in Germany. (glassonline.com)
  • The sulfhydryl group also has a high affinity for heavy metals, so that proteins containing cysteine, such as metallothionein, will bind metals such as mercury, lead, and cadmium tightly. (wikipedia.org)
  • Indeed, it has been demonstrated that cysteines are characterized by the most extreme conservation pattern, being highly conserved in functional positions of proteins but poorly conserved otherwise [ 5 ]. (hindawi.com)
  • In proteins where cysteine is not within the active site, activity can be modulated by changing conformation or by influencing its regulatory role, for example, iron sulfur complexes (ISCs) in aconitase possess cysteines required for its activity [ 7 ]. (hindawi.com)
  • In addition, an in vitro administration of cystine, but not cysteine, to human endothelial cells increased Cyp1a1 expression, supporting cystine as a putative AhR activator. (unl.pt)
  • While glutamic acid is usually sufficient because amino acid nitrogen is recycled through glutamate as an intermediary, dietary cysteine and glycine supplementation can improve synthesis of glutathione. (wikipedia.org)
  • Glutathione Synthesis Is Diminished in Patients With Uncontrolled Diabetes and Restored by Dietary Supplementation With Cysteine and Glycine. (findaphd.com)
  • Mucosal presence and activity of cysteine PI and cathepsin B have also been investigated in the pathogenesis of chemically induced HML. (jci.org)
  • Stopped-flow kinetics showed that the inhibition of the lysosomal cysteine proteinase, cathepsin B, by its endogenous inhibitor, cystatin C, occurs by a two-step mechanism, in which an initial, weak interaction is followed by a conformational change. (lu.se)
  • The presence of this loop, which allows the enzyme to function as an exopeptidase, thus complicates the inhibition mechanism, rendering cathepsin B much less susceptible than other cysteine. (lu.se)
  • article{d5c1ff8e-0690-4d5e-85b5-097b38cc0bdd, abstract = {{Stopped-flow kinetics showed that the inhibition of the lysosomal cysteine proteinase, cathepsin B, by its endogenous inhibitor, cystatin C, occurs by a two-step mechanism, in which an initial, weak interaction is followed by a conformational change. (lu.se)
  • This new cysteine derivative shows a potent mucolytic-expectorant activity in different test systems. (curehunter.com)
  • In diabetics, hyperglycaemia causes long-term health complications, because elevated levels of glycolytic intermediates (dihydroxyacetone phosphate (DHAP) and glyceraldehyde-3-phosphate (GAP)) causing oxidative stress, which depletes intracellular glutathione and cysteine. (findaphd.com)
  • The enzyme cystathionine gamma-lyase converts the cystathionine into cysteine and alpha-ketobutyrate. (wikipedia.org)
  • The enzyme cysteine synthase, using sulfide sources, converts this ester into cysteine, releasing acetate. (wikipedia.org)
  • Cysteine sulfoxides are important secondary compounds in Allium sativum and A. cepa, and have been known as substrates specific for enzyme alliinase. (uni-marburg.de)
  • The crystal structure of a cysteine protease ervatamin B, isolated from the medicinal plant Ervatamia coronaria, has been determined at 1.63 A. The unknown primary structure of the enzyme could also be traced from the high-quality electron density map. (rcsb.org)
  • NAC is a well-absorbed supplemental form of cysteine, an amino acid required for the enzyme reaction that produces glutathione in the body. (healthrangerstore.com)
  • Glutathione biosynthesis is limited by the availability of cysteine. (findaphd.com)
  • However, most living organisms keep their cysteines configured to the L-cysteine format, n-acetylcysteine. (brenntag.com)
  • It will underpin future development of cysteine rich diets as a way to lower the long term health complications caused by hyperglycaemia in diabetics It will also establish the existence of an alternative intracellular reservoir for cysteine which could be of relevance across all living organisms. (findaphd.com)
  • Reversible modification of cysteines such as disulfide bond formation, glutathionylation, and nitrosylation may also be a means of protection from further, generally irreversible, modifications to sulfinic (-SO 2 H) or sulfonic (-SO 3 H) acids [ 9 ]. (hindawi.com)
  • Clickable Glutathione-Based Identification of Cysteine Glutathionylation. (bvsalud.org)
  • MDL 28170 is a cell permeable selective inhibitor of Calpain 1, a Ca2+-dependent cysteine protease which has been implicated in apoptosis of immune cells as well as neuronal cells. (adooq.com)
  • The cysteine sulfhydryl group is nucleophilic and easily oxidized. (wikipedia.org)
  • Because of its high reactivity, the sulfhydryl group of cysteine has numerous biological functions. (wikipedia.org)
  • AM from DEP-exposed rats showed a time-dependent increase in intracellular cysteine (CYSH) and GSH. (cdc.gov)
  • N-acetyl-l-cysteine-commonly referred to as NAC -is a stable form of the amino acid cysteine. (fairhavenhealth.com)
  • N-Acetyl-L-Cysteine, or N-A-C, is an acetylated form of the amino acid cysteine. (feelgoodnatural.com)
  • NAC is a more stable form of L-Cysteine because it has an acetyl group (CH3CO) attached. (nutrabio.com)
  • We have recently discovered that cysteine can be chemically trapped by reaction with DHAP and GAP to form thiohemiacetals. (findaphd.com)
  • NAC is the most common and preferred form of amino acid cysteine. (nutritionexpress.com)
  • We hypothesized that an interplay between aryl hydrocarbon receptor (AhR) and cysteine-related thiolome at the kidney cortex underlies the mechanisms of (mal)adaptation to chronic intermittent hypoxia (CIH), promoting arterial hypertension (HTN). (unl.pt)
  • Once that organism dies, the body can no longer keep their cysteines configured accordingly, and it converts to the D-cysteine version. (brenntag.com)
  • Wacker has started commercial production on fermentation-derived L-cysteine, which will be marketed and sold in the US by Kyowa Hakko. (glassonline.com)
  • Animal studies at the Medical University of South Carolina have found that N-acetly-cysteine can lower levels of brain glutamate). (drweil.com)
  • In general, cysteines enhance the body's ability to create antioxidants. (brenntag.com)
  • Although classified as a nonessential amino acid, in rare cases, cysteine may be essential for infants, the elderly, and individuals with certain metabolic diseases or who suffer from malabsorption syndromes. (wikipedia.org)
  • As a dietary supplement, N-acetyl-L-cysteine supports comprehensive health in a variety of ways, including promoting normal liver function. (lifeextension.com)
  • For instance, certain food and nutrition laboratory services have developed formulation solutions that directly synthesize cysteines. (brenntag.com)
  • In the translation of messenger RNA molecules to produce polypeptides, cysteine is coded for by the UGU and UGC codons. (wikipedia.org)
  • N-Acetyl-L-Cysteine (NAC) provides powerful immune support and also packs a powerful anti-toxin potential. (nutrabio.com)
  • Different types of cysteine sulfoxides have been identified in many of Allium species, of which methiin, alliin, propiin, butiin and marasmin are some. (uni-marburg.de)
  • In this study, transgenic Leishmania tarentolae expressing gamma glutamyl cysteine synthetase (Ī³GCS) from three pathogenic species were produced and their ability to protect against infection determined using models of cutaneous and visceral leishmaniasis. (strath.ac.uk)
  • Finding reputable manufacturers that use this strategy makes it possible for vegans, vegetarians, and others to take advantage of the benefits of L-cysteine by using a synthetic version. (brenntag.com)
  • Warning: If you are pregnant or breastfeeding, consult your health care professional before using L-Cysteine product. (vitasprings.com)
  • N-Acetyl-L-Cysteine has the ability to neutralize cell and DNA damaging free radicals. (nutrabio.com)