Amino Acids: 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.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Amino Acid Sequence: 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.Amino Acid Substitution: 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.Cloning, Molecular: 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.Amino Acids, Essential: Amino acids that are not synthesized by the human body in amounts sufficient to carry out physiological functions. They are obtained from dietary foodstuffs.Amino Acid Transport Systems: Cellular proteins and protein complexes that transport amino acids across biological membranes.Sequence Alignment: 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.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Amino Acid Motifs: Commonly observed structural components of proteins formed by simple combinations of adjacent secondary structures. A commonly observed structure may be composed of a CONSERVED SEQUENCE which can be represented by a CONSENSUS SEQUENCE.Molecular Sequence Data: 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.Escherichia coli: 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.Mutation: 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.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Mutagenesis, Site-Directed: Genetically engineered MUTAGENESIS at a specific site in the DNA molecule that introduces a base substitution, or an insertion or deletion.DNA, Complementary: 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.Sequence Homology, Nucleic Acid: The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Kinetics: The rate dynamics in chemical or physical systems.Amino Acids, Aromatic: Amino acids containing an aromatic side chain.Recombinant Proteins: Proteins prepared by recombinant DNA technology.Protein Conformation: 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).Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.Amino Acids, Branched-Chain: Amino acids which have a branched carbon chain.Amino Acids, SulfurLeucine: An essential branched-chain amino acid important for hemoglobin formation.Protein Structure, Tertiary: 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.Structure-Activity Relationship: 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.Protein Binding: 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.DNA: A deoxyribonucleotide polymer that is the primary genetic material of all cells. Eukaryotic and prokaryotic organisms normally contain DNA in a double-stranded state, yet several important biological processes transiently involve single-stranded regions. DNA, which consists of a polysugar-phosphate backbone possessing projections of purines (adenine and guanine) and pyrimidines (thymine and cytosine), forms a double helix that is held together by hydrogen bonds between these purines and pyrimidines (adenine to thymine and guanine to cytosine).Peptides: 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.Substrate Specificity: A characteristic feature of enzyme activity in relation to the kind of substrate on which the enzyme or catalytic molecule reacts.Molecular Weight: The sum of the weight of all the atoms in a molecule.Bacterial Proteins: Proteins found in any species of bacterium.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Restriction Mapping: Use of restriction endonucleases to analyze and generate a physical map of genomes, genes, or other segments of DNA.Phylogeny: The relationships of groups of organisms as reflected by their genetic makeup.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.Proteins: 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.Sequence Analysis, DNA: A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.RNA, Messenger: RNA sequences that serve as templates for protein synthesis. Bacterial mRNAs are generally primary transcripts in that they do not require post-transcriptional processing. Eukaryotic mRNA is synthesized in the nucleus and must be exported to the cytoplasm for translation. Most eukaryotic mRNAs have a sequence of polyadenylic acid at the 3' end, referred to as the poly(A) tail. The function of this tail is not known for certain, but it may play a role in the export of mature mRNA from the nucleus as well as in helping stabilize some mRNA molecules by retarding their degradation in the cytoplasm.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Alanine: 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.Genes, Bacterial: The functional hereditary units of BACTERIA.Protein Structure, Secondary: 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.Amino Acid Transport Systems, Basic: Amino acid transporter systems capable of transporting basic amino acids (AMINO ACIDS, BASIC).Plasmids: 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.Conserved Sequence: 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.Lysine: An essential amino acid. It is often added to animal feed.Species Specificity: The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.DNA Primers: 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.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Isoleucine: An essential branched-chain aliphatic amino acid found in many proteins. It is an isomer of LEUCINE. It is important in hemoglobin synthesis and regulation of blood sugar and energy levels.Carrier Proteins: Transport proteins that carry specific substances in the blood or across cell membranes.Amino Acids, Basic: Amino acids with side chains that are positively charged at physiological pH.Cattle: 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.Codon: A set of three nucleotides in a protein coding sequence that specifies individual amino acids or a termination signal (CODON, TERMINATOR). Most codons are universal, but some organisms do not produce the transfer RNAs (RNA, TRANSFER) complementary to all codons. These codons are referred to as unassigned codons (CODONS, NONSENSE).Amino Acids, DiaminoTrypsin: 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.Biological Transport: The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.Cyanogen Bromide: Cyanogen bromide (CNBr). A compound used in molecular biology to digest some proteins and as a coupling reagent for phosphoroamidate or pyrophosphate internucleotide bonds in DNA duplexes.Arginine: An essential amino acid that is physiologically active in the L-form.Glycine: 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.Genes: A category of nucleic acid sequences that function as units of heredity and which code for the basic instructions for the development, reproduction, and maintenance of organisms.Open Reading Frames: A sequence of successive nucleotide triplets that are read as CODONS specifying AMINO ACIDS and begin with an INITIATOR CODON and end with a stop codon (CODON, TERMINATOR).Protein Biosynthesis: The biosynthesis of PEPTIDES and PROTEINS on RIBOSOMES, directed by MESSENGER RNA, via TRANSFER RNA that is charged with standard proteinogenic AMINO ACIDS.Glutamine: A non-essential amino acid present abundantly throughout the body and is involved in many metabolic processes. It is synthesized from GLUTAMIC ACID and AMMONIA. It is the principal carrier of NITROGEN in the body and is an important energy source for many cells.Saccharomyces cerevisiae: A species of the genus SACCHAROMYCES, family Saccharomycetaceae, order Saccharomycetales, known as "baker's" or "brewer's" yeast. The dried form is used as a dietary supplement.Polymerase Chain Reaction: In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.Gene Library: A large collection of DNA fragments cloned (CLONING, MOLECULAR) from a given organism, tissue, organ, or cell type. It may contain complete genomic sequences (GENOMIC LIBRARY) or complementary DNA sequences, the latter being formed from messenger RNA and lacking intron sequences.Sequence Deletion: Deletion of sequences of nucleic acids from the genetic material of an individual.Valine: A branched-chain essential amino acid that has stimulant activity. It promotes muscle growth and tissue repair. It is a precursor in the penicillin biosynthetic pathway.Transcription, Genetic: The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.Methionine: A sulfur-containing essential L-amino acid that is important in many body functions.Sequence Analysis: A multistage process that includes the determination of a sequence (protein, carbohydrate, etc.), its fragmentation and analysis, and the interpretation of the resulting sequence information.Excitatory Amino Acids: Endogenous amino acids released by neurons as excitatory neurotransmitters. Glutamic acid is the most common excitatory neurotransmitter in the brain. Aspartic acid has been regarded as an excitatory transmitter for many years, but the extent of its role as a transmitter is unclear.Aspartic Acid: One of the non-essential amino acids commonly occurring in the L-form. It is found in animals and plants, especially in sugar cane and sugar beets. It may be a neurotransmitter.Mutagenesis: Process of generating a genetic MUTATION. It may occur spontaneously or be induced by MUTAGENS.Transfection: 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.Proline: A non-essential amino acid that is synthesized from GLUTAMIC ACID. It is an essential component of COLLAGEN and is important for proper functioning of joints and tendons.Point Mutation: 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.Nitrogen: An element with the atomic symbol N, atomic number 7, and atomic weight [14.00643; 14.00728]. Nitrogen exists as a diatomic gas and makes up about 78% of the earth's atmosphere by volume. It is a constituent of proteins and nucleic acids and found in all living cells.Phenylalanine: An essential aromatic amino acid that is a precursor of MELANIN; DOPAMINE; noradrenalin (NOREPINEPHRINE), and THYROXINE.Membrane Proteins: 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.Cysteine: A thiol-containing non-essential amino acid that is oxidized to form CYSTINE.Tryptophan: An essential amino acid that is necessary for normal growth in infants and for NITROGEN balance in adults. It is a precursor of INDOLE ALKALOIDS in plants. It is a precursor of SEROTONIN (hence its use as an antidepressant and sleep aid). It can be a precursor to NIACIN, albeit inefficiently, in mammals.Amino Acid Transport System A: A sodium-dependent neutral amino acid transporter that accounts for most of the sodium-dependent neutral amino acid uptake by mammalian cells. The preferred substrates for this transporter system include ALANINE; SERINE; and GLUTAMINE.Amino Acids, Neutral: Amino acids with uncharged R groups or side chains.Gene Expression: The phenotypic manifestation of a gene or genes by the processes of GENETIC TRANSCRIPTION and GENETIC TRANSLATION.Blotting, Northern: Detection of RNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.Macromolecular Substances: Compounds and molecular complexes that consist of very large numbers of atoms and are generally over 500 kDa in size. In biological systems macromolecular substances usually can be visualized using ELECTRON MICROSCOPY and are distinguished from ORGANELLES by the lack of a membrane structure.Evolution, Molecular: The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.Viral Proteins: Proteins found in any species of virus.Plant Proteins: Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which VEGETABLE PROTEINS is available.DNA-Binding Proteins: Proteins which bind to DNA. The family includes proteins which bind to both double- and single-stranded DNA and also includes specific DNA binding proteins in serum which can be used as markers for malignant diseases.DNA, Bacterial: Deoxyribonucleic acid that makes up the genetic material of bacteria.Sequence Analysis, Protein: A process that includes the determination of AMINO ACID SEQUENCE of a protein (or peptide, oligopeptide or peptide fragment) and the information analysis of the sequence.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Protein PrecursorsChromatography, Gel: Chromatography on non-ionic gels without regard to the mechanism of solute discrimination.Threonine: An essential amino acid occurring naturally in the L-form, which is the active form. It is found in eggs, milk, gelatin, and other proteins.Hydrolysis: The process of cleaving a chemical compound by the addition of a molecule of water.Swine: Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).COS Cells: 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).)Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Chromatography, Ion Exchange: Separation technique in which the stationary phase consists of ion exchange resins. The resins contain loosely held small ions that easily exchange places with other small ions of like charge present in solutions washed over the resins.Epitopes: Sites on an antigen that interact with specific antibodies.Transcription Factors: Endogenous substances, usually proteins, which are effective in the initiation, stimulation, or termination of the genetic transcription process.Cell Membrane: The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.Endopeptidases: A subclass of PEPTIDE HYDROLASES that catalyze the internal cleavage of PEPTIDES or PROTEINS.Protein Processing, Post-Translational: 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.Protein Sorting Signals: Amino acid sequences found in transported proteins that selectively guide the distribution of the proteins to specific cellular compartments.Receptors, Amino Acid: Cell surface proteins that bind amino acids and trigger changes which influence the behavior of cells. Glutamate receptors are the most common receptors for fast excitatory synaptic transmission in the vertebrate central nervous system, and GAMMA-AMINOBUTYRIC ACID and glycine receptors are the most common receptors for fast inhibition.Chymotrypsin: A serine endopeptidase secreted by the pancreas as its zymogen, CHYMOTRYPSINOGEN and carried in the pancreatic juice to the duodenum where it is activated by TRYPSIN. It selectively cleaves aromatic amino acids on the carboxyl side.Dietary Proteins: Proteins obtained from foods. They are the main source of the ESSENTIAL AMINO ACIDS.Cricetinae: A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.Chickens: Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.Serine: A non-essential amino acid occurring in natural form as the L-isomer. It is synthesized from GLYCINE or THREONINE. It is involved in the biosynthesis of PURINES; PYRIMIDINES; and other amino acids.Multigene Family: A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)Cells, Cultured: 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.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Fungal Proteins: Proteins found in any species of fungus.Repetitive Sequences, Amino Acid: A sequential pattern of amino acids occurring more than once in the same protein sequence.Peptide Mapping: 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.Genetic Complementation Test: A test used to determine whether or not complementation (compensation in the form of dominance) will occur in a cell with a given mutant phenotype when another mutant genome, encoding the same mutant phenotype, is introduced into that cell.Amino Acids, Cyclic: A class of amino acids characterized by a closed ring structure.Hydrogen-Ion Concentration: 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)DNA Mutational Analysis: Biochemical identification of mutational changes in a nucleotide sequence.Temperature: The property of objects that determines the direction of heat flow when they are placed in direct thermal contact. The temperature is the energy of microscopic motions (vibrational and translational) of the particles of atoms.Glutamic Acid: A non-essential amino acid naturally occurring in the L-form. Glutamic acid is the most common excitatory neurotransmitter in the CENTRAL NERVOUS SYSTEM.Blotting, Southern: A method (first developed by E.M. Southern) for detection of DNA that has been electrophoretically separated and immobilized by blotting on nitrocellulose or other type of paper or nylon membrane followed by hybridization with labeled NUCLEIC ACID PROBES.Aminoisobutyric Acids: A group of compounds that are derivatives of the amino acid 2-amino-2-methylpropanoic acid.Amino Acyl-tRNA Synthetases: A subclass of enzymes that aminoacylate AMINO ACID-SPECIFIC TRANSFER RNA with their corresponding AMINO ACIDS.Circular Dichroism: 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)Chromosome Mapping: Any method used for determining the location of and relative distances between genes on a chromosome.Escherichia coli Proteins: Proteins obtained from ESCHERICHIA COLI.Oligopeptides: Peptides composed of between two and twelve amino acids.Amino Acids, Acidic: Amino acids with side chains that are negatively charged at physiological pH.Genetic Variation: Genotypic differences observed among individuals in a population.Phenotype: The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.Carbon Isotopes: Stable carbon atoms that have the same atomic number as the element carbon, but differ in atomic weight. C-13 is a stable carbon isotope.Oligodeoxyribonucleotides: A group of deoxyribonucleotides (up to 12) in which the phosphate residues of each deoxyribonucleotide act as bridges in forming diester linkages between the deoxyribose moieties.Serine Endopeptidases: Any member of the group of ENDOPEPTIDASES containing at the active site a serine residue involved in catalysis.Oligonucleotide Probes: Synthetic or natural oligonucleotides used in hybridization studies in order to identify and study specific nucleic acid fragments, e.g., DNA segments near or within a specific gene locus or gene. The probe hybridizes with a specific mRNA, if present. Conventional techniques used for testing for the hybridization product include dot blot assays, Southern blot assays, and DNA:RNA hybrid-specific antibody tests. Conventional labels for the probe include the radioisotope labels 32P and 125I and the chemical label biotin.Enzyme Stability: 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.Genes, Fungal: The functional hereditary units of FUNGI.Mass Spectrometry: An analytical method used in determining the identity of a chemical based on its mass using mass analyzers/mass spectrometers.Magnetic Resonance Spectroscopy: Spectroscopic method of measuring the magnetic moment of elementary particles such as atomic nuclei, protons or electrons. It is employed in clinical applications such as NMR Tomography (MAGNETIC RESONANCE IMAGING).Tyrosine: A non-essential amino acid. In animals it is synthesized from PHENYLALANINE. It is also the precursor of EPINEPHRINE; THYROID HORMONES; and melanin.Cystine: 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.Large Neutral Amino Acid-Transporter 1: A CD98 antigen light chain that when heterodimerized with CD98 antigen heavy chain (ANTIGENS, CD98 HEAVY CHAIN) forms a protein that mediates sodium-independent L-type amino acid transport.Time Factors: Elements of limited time intervals, contributing to particular results or situations.Exons: The parts of a transcript of a split GENE remaining after the INTRONS are removed. They are spliced together to become a MESSENGER RNA or other functional RNA.Culture Media: Any liquid or solid preparation made specifically for the growth, storage, or transport of microorganisms or other types of cells. The variety of media that exist allow for the culturing of specific microorganisms and cell types, such as differential media, selective media, test media, and defined media. Solid media consist of liquid media that have been solidified with an agent such as AGAR or GELATIN.Phosphorylation: The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.Molecular Structure: 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.Tissue Distribution: Accumulation of a drug or chemical substance in various organs (including those not relevant to its pharmacologic or therapeutic action). This distribution depends on the blood flow or perfusion rate of the organ, the ability of the drug to penetrate organ membranes, tissue specificity, protein binding. The distribution is usually expressed as tissue to plasma ratios.Carbohydrates: The largest class of organic compounds, including STARCH; GLYCOGEN; CELLULOSE; POLYSACCHARIDES; and simple MONOSACCHARIDES. Carbohydrates are composed of carbon, hydrogen, and oxygen in a ratio of Cn(H2O)n.Sequence Homology: The degree of similarity between sequences. Studies of AMINO ACID SEQUENCE HOMOLOGY and NUCLEIC ACID SEQUENCE HOMOLOGY provide useful information about the genetic relatedness of genes, gene products, and species.Chemistry: A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.HeLa Cells: The first continuously cultured human malignant CELL LINE, derived from the cervical carcinoma of Henrietta Lacks. These cells are used for VIRUS CULTIVATION and antitumor drug screening assays.Cercopithecus aethiops: A species of CERCOPITHECUS containing three subspecies: C. tantalus, C. pygerythrus, and C. sabeus. They are found in the forests and savannah of Africa. The African green monkey (C. pygerythrus) is the natural host of SIMIAN IMMUNODEFICIENCY VIRUS and is used in AIDS research.Crystallography, X-Ray: The study of crystal structure using X-RAY DIFFRACTION techniques. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Asparagine: A non-essential amino acid that is involved in the metabolic control of cell functions in nerve and brain tissue. It is biosynthesized from ASPARTIC ACID and AMMONIA by asparagine synthetase. (From Concise Encyclopedia Biochemistry and Molecular Biology, 3rd ed)RNA: A polynucleotide consisting essentially of chains with a repeating backbone of phosphate and ribose units to which nitrogenous bases are attached. RNA is unique among biological macromolecules in that it can encode genetic information, serve as an abundant structural component of cells, and also possesses catalytic activity. (Rieger et al., Glossary of Genetics: Classical and Molecular, 5th ed)Isoenzymes: Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.Saccharomyces cerevisiae Proteins: Proteins obtained from the species SACCHAROMYCES CEREVISIAE. The function of specific proteins from this organism are the subject of intense scientific interest and have been used to derive basic understanding of the functioning similar proteins in higher eukaryotes.Protein Folding: Processes involved in the formation of TERTIARY PROTEIN STRUCTURE.Stereoisomerism: The phenomenon whereby compounds whose molecules have the same number and kind of atoms and the same atomic arrangement, but differ in their spatial relationships. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 5th ed)Genetic Code: The meaning ascribed to the BASE SEQUENCE with respect to how it is translated into AMINO ACID SEQUENCE. The start, stop, and order of amino acids of a protein is specified by consecutive triplets of nucleotides called codons (CODON).Dimerization: The process by which two molecules of the same chemical composition form a condensation product or polymer.Chemical Phenomena: The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.Consensus Sequence: A theoretical representative nucleotide or amino acid sequence in which each nucleotide or amino acid is the one which occurs most frequently at that site in the different sequences which occur in nature. The phrase also refers to an actual sequence which approximates the theoretical consensus. A known CONSERVED SEQUENCE set is represented by a consensus sequence. Commonly observed supersecondary protein structures (AMINO ACID MOTIFS) are often formed by conserved sequences.Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.Caseins: A mixture of related phosphoproteins occurring in milk and cheese. The group is characterized as one of the most nutritive milk proteins, containing all of the common amino acids and rich in the essential ones.Plants: Multicellular, eukaryotic life forms of kingdom Plantae (sensu lato), comprising the VIRIDIPLANTAE; RHODOPHYTA; and GLAUCOPHYTA; all of which acquired chloroplasts by direct endosymbiosis of CYANOBACTERIA. They are characterized by a mainly photosynthetic mode of nutrition; essentially unlimited growth at localized regions of cell divisions (MERISTEMS); cellulose within cells providing rigidity; the absence of organs of locomotion; absence of nervous and sensory systems; and an alternation of haploid and diploid generations.Mutation, Missense: A mutation in which a codon is mutated to one directing the incorporation of a different amino acid. This substitution may result in an inactive or unstable product. (From A Dictionary of Genetics, King & Stansfield, 5th ed)Chromatography, Affinity: A chromatographic technique that utilizes the ability of biological molecules to bind to certain ligands specifically and reversibly. It is used in protein biochemistry. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Gene Expression Regulation: Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.Histidine: An essential amino acid that is required for the production of HISTAMINE.Genes, Viral: The functional hereditary units of VIRUSES.Catalytic Domain: The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.Glycosylation: The chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, especially peptides or proteins. Glycosyl transferases are used in this biochemical reaction.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.CHO Cells: CELL LINE derived from the ovary of the Chinese hamster, Cricetulus griseus (CRICETULUS). The species is a favorite for cytogenetic studies because of its small chromosome number. The cell line has provided model systems for the study of genetic alterations in cultured mammalian cells.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Xenopus laevis: The commonest and widest ranging species of the clawed "frog" (Xenopus) in Africa. This species is used extensively in research. There is now a significant population in California derived from escaped laboratory animals.DNA Restriction Enzymes: Enzymes that are part of the restriction-modification systems. They catalyze the endonucleolytic cleavage of DNA sequences which lack the species-specific methylation pattern in the host cell's DNA. Cleavage yields random or specific double-stranded fragments with terminal 5'-phosphates. The function of restriction enzymes is to destroy any foreign DNA that invades the host cell. Most have been studied in bacterial systems, but a few have been found in eukaryotic organisms. They are also used as tools for the systematic dissection and mapping of chromosomes, in the determination of base sequences of DNAs, and have made it possible to splice and recombine genes from one organism into the genome of another. EC 3.21.1.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Biological Evolution: The process of cumulative change over successive generations through which organisms acquire their distinguishing morphological and physiological characteristics.Fibroblast Growth Factor 2: A single-chain polypeptide growth factor that plays a significant role in the process of WOUND HEALING and is a potent inducer of PHYSIOLOGIC ANGIOGENESIS. Several different forms of the human protein exist ranging from 18-24 kDa in size due to the use of alternative start sites within the fgf-2 gene. It has a 55 percent amino acid residue identity to FIBROBLAST GROWTH FACTOR 1 and has potent heparin-binding activity. The growth factor is an extremely potent inducer of DNA synthesis in a variety of cell types from mesoderm and neuroectoderm lineages. It was originally named basic fibroblast growth factor based upon its chemical properties and to distinguish it from acidic fibroblast growth factor (FIBROBLAST GROWTH FACTOR 1).Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.Signal Transduction: The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.Gene Expression Regulation, Bacterial: Any of the processes by which cytoplasmic or intercellular factors influence the differential control of gene action in bacteria.Carboxypeptidases: Enzymes that act at a free C-terminus of a polypeptide to liberate a single amino acid residue.Solubility: The ability of a substance to be dissolved, i.e. to form a solution with another substance. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Nucleic Acid Hybridization: Widely used technique which exploits the ability of complementary sequences in single-stranded DNAs or RNAs to pair with each other to form a double helix. Hybridization can take place between two complimentary DNA sequences, between a single-stranded DNA and a complementary RNA, or between two RNA sequences. The technique is used to detect and isolate specific sequences, measure homology, or define other characteristics of one or both strands. (Kendrew, Encyclopedia of Molecular Biology, 1994, p503)Cytoplasm: The part of a cell that contains the CYTOSOL and small structures excluding the CELL NUCLEUS; MITOCHONDRIA; and large VACUOLES. (Glick, Glossary of Biochemistry and Molecular Biology, 1990)Oxidation-Reduction: 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).Protein Engineering: 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.Transaminases: A subclass of enzymes of the transferase class that catalyze the transfer of an amino group from a donor (generally an amino acid) to an acceptor (generally a 2-keto acid). Most of these enzymes are pyridoxyl phosphate proteins. (Dorland, 28th ed) EC 2.6.1.

Anti-sm autoantibodies in systemic lupus target highly basic surface structures of complexed spliceosomal autoantigens. (1/107)

Autoantibodies directed against spliceosomal proteins are a common and specific feature of systemic lupus erythematosus. These autoantibodies target a collection of proteins, including Sm B, B', D1, D2, and D3. We define the common antigenic targets of Sm D2 and D3 and examine their role in spliceosomal autoimmunity. Our results define nine major common epitopes, five on Sm D2 and four on Sm D3. These epitopes have significantly higher (more basic) isoelectric points than do nonantigenic regions. In fact, this association is of sufficient power to make isoelectric point an excellent predictor of spliceosomal antigenicity. The crystallographic structure of Sm D2 and D3 is now partially described. The anti-Sm D2 and D3 antigenic targets are located on the surface of the respective three-dimensional complexed proteins, thereby suggesting that these epitopes are accessible in the native configuration. All but one of these nine epitopes conspicuously avoid the specific regions involved in intermolecular interactions within the spliceosomal complex. One of the D3 epitopes (RGRGRGMGR) has significant sequence homology with a major antigenic region of Sm D1 (containing a carboxyl-terminal glycine-arginine repeat), and anti-D3 Abs cross-react with this epitope of Sm D1. These results demonstrate that spliceosomal targets of autoimmunity are accessible on native structure surfaces and that cross-reactive epitopes, as well as structural associations of various spliceosomal Ags, may be involved in the induction of autoimmunity in systemic lupus.  (+info)

Membrane activity of the southern cowpea mosaic virus coat protein: the role of basic amino acids, helix-forming potential, and lipid composition. (2/107)

Southern cowpea mosaic virus (SCPMV) is a spherical RNA virus with T = 3 icosahedral symmetry. The particle is composed of 180 subunits of the coat protein (CP) and one copy of the positive-sense viral RNA. The CP has two domains, the random (R) domain formed by the N-terminal 64 aa and the shell (S) domain (aa 65--260). The R domain is highly charged, with 11 of the N-terminal 30 residues being basic. It is localized to the interior of the native particle where it may interact with the viral RNA, but under certain pH and salt conditions the topology of the particle changes to externalize the R domain. Since the CPs of several spherical RNA viruses have been shown to interact with host membranes during infection, we have begun investigating the membrane interactions of the SCPMV CP using the artificial liposome membranes. Both the native CP and the R domain overexpressed in Escherichia coli were observed to interact with liposomes. The interaction between the R domain and liposomes required either anionic phospholipids or non-bilayer-forming lipids and involved electrostatic interactions since it was shown to be both pH and ionic strength dependent. The analysis of four different deletion and six different site-directed substitution mutations partially mapped the region responsible for this interaction to residues 1--30. Analysis of this region of the R domain by circular dichroism indicated that it assumes an alpha-helical structure when exposed to liposomes composed of anionic lipids. Mutations, which extend the helical nature of this region, promoted an increased interaction. The possible role of the CP/lipid interaction in the SCPMV infection is discussed.  (+info)

Characterization of signal that directs C-tail-anchored proteins to mammalian mitochondrial outer membrane. (3/107)

We analyzed the signal that directs the outer membrane protein with the C-terminal transmembrane segment (TMS) to mammalian mitochondria by using yeast Tom5 as a model and green fluorescent protein as a reporter. Deletions or mutations were systematically introduced into the TMS or the flanking regions and their intracellular localization in COS-7 cells was examined using confocal microscopy and cell fractionation. 1) Three basic amino acid residues within the C-terminal five-residue segment (C-segment) contained the information required for mitochondrial-targeting. Reduction of the net positive charge in this segment decreased mitochondrial specificity, and the mutants were distributed throughout the intracellular membranes. 2) Elongation of the TMS interfered with the function of the C-segment and the mutants were delivered to the intracellular membranes. 3) Separation of the TMS and C-segment by linker insertion severely impaired mitochondrial targeting function, leading to mislocalization to the cytoplasm. 4) Mutations or small deletions in the region of the TMS flanking the C-segment also impaired the mitochondrial targeting. Therefore, the moderate length of the TMS, the positive charges in the C-segment, and the distance between or context of the TMS and C-segment are critical for the targeting signal. The structural characteristics of the signal thus defined were also confirmed with mammalian C-tail-anchored protein OMP25.  (+info)

Covalent cross-linking of proteins without chemical reagents. (4/107)

A facile method for the formation of zero-length covalent cross-links between protein molecules in the lyophilized state without the use of chemical reagents has been developed. The cross-linking process is performed by simply sealing lyophilized protein under vacuum in a glass vessel and heating at 85 degrees C for 24 h. Under these conditions, approximately one-third of the total protein present becomes cross-linked, and dimer is the major product. Chemical and mass spectroscopic evidence obtained shows that zero-length cross-links are formed as a result of the condensation of interacting ammonium and carboxylate groups to form amide bonds between adjacent molecules. For the protein examined in the most detail, RNase A, the cross-linked dimer has only one amide cross-link and retains the enzymatic activity of the monomer. The in vacuo cross-linking procedure appears to be general in its applicability because five different proteins tested gave substantial cross-linking, and co-lyophilization of lysozyme and RNase A also gave a heterogeneous covalently cross-linked dimer.  (+info)

Role of paired basic residues of protein C-termini in phospholipid binding. (5/107)

It is a well known phenomenon that the occurrence of several distinct amino acids at the C-terminus of proteins is non-random. We have analysed all Saccharomyces cerevisiae proteins predicted by computer databases and found lysine to be the most frequent residue both at the last (-1) and at the penultimate amino acid (-2) positions. To test the hypothesis that C-terminal basic residues efficiently bind to phospholipids we randomly expressed GST-fusion proteins from a yeast genomic library. Fifty-four different peptide fragments were found to bind phospholipids and 40% of them contained lysine/arginine residues at the (-1) or (-2) positions. One peptide showed high sequence similarity with the yeast protein Sip18p. Mutational analysis revealed that both C-terminal lysine residues of Sip18p are essential for phospholipid-binding in vitro. We assume that basic amino acid residues at the (-1) and (-2) positions in C-termini are suitable to attach the C-terminus of a given protein to membrane components such as phospholipids, thereby stabilizing the spatial structure of the protein or contributing to its subcellular localization. This mechanism could be an additional explanation for the C-terminal amino acid bias observed in proteins of several species.  (+info)

Contribution of basic residues of the A helix of heparin cofactor II to heparin- or dermatan sulfate-mediated thrombin inhibition. (6/107)

Inhibition of thrombin by heparin cofactor II (HCII) is accelerated 1000-fold by heparin or dermatan sulfate. To investigate the contribution of basic residues of the A helix of HCII to this activation, we constructed amino acid substitutions (K101Q, R103L, and R106L) by site-directed mutagenesis. K101Q greatly reduced heparin cofactor activity and required a more than 10-fold higher concentration of dermatan sulfate to accelerate thrombin inhibition compared with wild-type recombinant HCII. Thrombin inhibition by R106L was not significantly stimulated by dermatan sulfate. These results provide evidence that basic residues of the A helix of HCII (Lys(101) and Arg(106)) are necessary for heparin- or dermatan sulfate-accelerated thrombin inhibition.  (+info)

Site-directed mutagenesis of conserved charged amino acid residues in ClpB from Escherichia coli. (7/107)

ClpB is a member of a multichaperone system in Escherichia coli (with DnaK, DnaJ, and GrpE) that reactivates strongly aggregated proteins. The sequence of ClpB contains two ATP-binding domains, each containing Walker consensus motifs. The N- and C-terminal sequence regions of ClpB do not contain known functional motifs. In this study, we performed site-directed mutagenesis of selected charged residues within the Walker A motifs (Lys212 and Lys611) and the C-terminal region of ClpB (Asp797, Arg815, Arg819, and Glu826). We found that the mutations K212T, K611T, D797A, R815A, R819A, and E826A did not significantly affect the secondary structure of ClpB. The mutation of the N-terminal ATP-binding site (K212T), but not of the C-terminal ATP-binding site (K611T), and two mutations within the C-terminal domain (R815A and R819A) inhibited the self-association of ClpB in the absence of nucleotides. The defects in self-association of these mutants were also observed in the presence of ATP and ADP. The four mutants K212T, K611T, R815A, and R819A showed an inhibition of chaperone activity, which correlated with their low ATPase activity in the presence of casein. Our results indicate that positively charged amino acids that are located along the intersubunit interface (this includes Lys212 in the Walker A motif of the N-terminal ATP-binding domain as well as Arg815 and Arg819 in the C-terminal domain) participate in intersubunit salt bridges and stabilize the ClpB oligomer. Interestingly, we have identified a conserved residue within the C-terminal domain (Arg819) which does not participate directly in nucleotide binding but is essential for the chaperone activity of ClpB.  (+info)

Complete replacement of basic amino acid residues with cysteines in Rickettsia prowazekii ATP/ADP translocase. (8/107)

The ATP/ADP translocase (Tlc) of Rickettsia prowazekii is a basic protein with isoelectric point (pI)=9.84. It is conceivable, therefore, that basic residues in this protein are involved in electrostatic interactions with negatively charged substrates. We tested this hypothesis by individually mutating all basic residues in Tlc to Cys. Unexpectedly, mutations of only 20 out of 51 basic residues resulted in greater than 80% inhibition of transport activity. Moreover, 12 of 51Cys-substitution mutants exhibited higher than wild-type (WT) activity. At least in one case this up-effect was additive and the double mutant Lys422Cys Lys427Cys transported ATP five-fold better than WT protein. Since in these two single mutants and in the corresponding double mutant K(m)'s were similar to that of WT protein, we conclude that Tlc may have evolved a mechanism that limits the transporter's exchange rate and that at least these two basic residues play a key role in that mechanism. Based on the alignment of 16 Tlc homologs, the loss of activity in the mutants poorly correlates with charge conservation within the Tlc family. Also, despite the presence of three positively charged and one negatively charged intramembrane residues, we have failed to identify potential charge pairs (salt bridges) by either charge reversal or charge neutralization approaches.  (+info)

  • NMR measurements revealed that levels of branched-chain amino acids (BCAAs) and the valine metabolite 3-hydroxyisobyturate were higher in T2DM and IGT groups and correlated with measures of insulin resistance and lipid metabolism. (hindawi.com)
  • One example of the enzyme in action occurs with the conversion L-alanine into pyruvic acid (2-oxopropanoic acid), as shown in Figure 1. (wikipedia.org)
  • A unique blend of 20 highest quality L-Crystalline singular amino acids, plus precursor Ornithine-Þ-Ketoglutarate and the superior antioxidant protection of Alpha Lipoic Acid for general health support. (forresthealth.com)
  • Plus precursor Ornithine-Þ-Ketoglutarate and the superior antioxidant protection of Alpha Lipoic Acid for general health support. (forresthealth.com)
  • Working with genetically engineered mice, Johns Hopkins neuroscientists report they have identified what they believe is the cause of the vast disintegration of a part of the brain called the corpus striatum in rodents and people with Huntington's disease: loss of the ability to make the amino acid cysteine. (hopkinsmedicine.org)
  • Bindu Diana Paul, Ph.D., a molecular neuroscientist and faculty instructor in Snyder's laboratory, was studying mice lacking CSE, which helps make the amino acid cysteine and hydrogen sulfide that moderate blood pressure and heart function. (hopkinsmedicine.org)
  • Considerable evidence implicates free fatty acids (FFAs) and other lipids that contribute to metabolic disease and insulin resistance. (hindawi.com)
  • When a basic amino acid is in an acidic medium (having a pH lower than 7 and containing the hydrogen ion [H. (thefreedictionary.com)
  • Acids are the compounds that donate a hydrogen ion (H+) to a base, while a base compound is one that can remove a proton (H+ is a proton) from an acid. (aminoco.com)
  • Hydrogen molecules are why bases and acids are often measured in pH levels (pH stands for "potential of hydrogen") as related to pure water. (aminoco.com)
  • When an acid is dissolved in water, it becomes a solution with higher hydrogen ion activity than water, making it more acidic, with a pH value less than 7. (aminoco.com)
  • Weak acids include formic acid, acetic acid, hydrofluoric acid, hydrogen sulfide and hydrocyanic acid. (reference.com)
  • Each of these acids has the same basic chemical structure, which includes a central carbon atom, a hydrogen atom, a group of atoms called an amino group and a group of atoms called a carboxyl group. (livestrong.com)
  • In an aqueous environment, the hydrophobic amino acids are unable to participate in hydrogen bonding. (wikibooks.org)
  • An acid is a molecule or ion capable of donating a hydron (proton or hydrogen ion H + ), or, alternatively, capable of forming a covalent bond with an electron pair (a Lewis acid). (wikipedia.org)
  • Common aqueous acids include hydrochloric acid (a solution of hydrogen chloride which is found in gastric acid in the stomach and activates digestive enzymes ), acetic acid (vinegar is a dilute aqueous solution of this liquid), sulfuric acid (used in car batteries ), and citric acid (found in citrus fruits). (wikipedia.org)
  • However, hydrogen chloride, acetic acid, and most other Brønsted-Lowry acids cannot form a covalent bond with an electron pair and are therefore not Lewis acids. (wikipedia.org)
  • The three substrates of the enzymatic reaction are an L-amino acid, water, and oxygen, whereas the three products are the corresponding α-keto acid (2-oxo acid), ammonia, and hydrogen peroxide. (wikipedia.org)
  • Often they produce higher than normal amounts of the corresponding natural amino acids, and, hence, growth in specific amino acid analog is used as a selection tool (1). (springer.com)
  • The comparison between 9 home-made amino acid- and peptide-silica stationary phases in hydrophilic interaction liquid chromatography (HILIC) and reversed-phase liquid chromatography (RP HPLC) systems has been presented. (springer.com)
  • 2. The peptide of claim 1 that is acylated at the amino terminus. (google.com)
  • An ASP carboxy-terminal peptide encompassing amino acids 83-131 has been generated via expression cloning and is purportedly as active as full length ASP (Willard et al. (google.com)
  • PCT patent application WO 97/43412 (published Nov. 20, 1997) describes an AGRP peptide of amino acids 79-132. (google.com)
  • In the case of HILIC mode, the characterization was performed in terms of the degree of hydrophilicity, selectivity for hydrophilic-hydrophobic compounds, selectivity for the regio and configurational substituents, anion and cation exchange properties, and acidic or basic nature of the stationary phase surface. (springer.com)
  • Amino acids can be broadly hydrophobic and hydrophilic , depending on the chemical properties of the R group side chain. (wikibooks.org)
  • Many studies show that a number of sv-LAAOs exhibit a preference for hydrophobic L-amino acids as substrates. (wikipedia.org)
  • Iodinated and brominated tyrosine are also amino acids found in species, but are not included in the 20 major amino acids because of their rarity: iodinated tyrosin is only found in thyroid hormones, and brominated tyrosine is only found in coral. (wikibooks.org)
  • These AMPs are based on the incorporation of three dipeptide units consisting of the unnatural amino acids Tic-Oic in the sequence, Ac-GF-Tic-Oic-GX-Tic-Oic-GF-Tic-Oic-GX-Tic-XXXX-CONH 2 , where X (Spacer #2) may be one of the following amino acids, Lys, Orn, Dab, Dpr or Arg. (elsevier.com)
  • J.M. Widholm, Selection and characterization of amino acid analog resistant plant cell cultures, Crop Sci. (springer.com)
  • Shorter sequences of amino acids (i.e. di-, tri-, and tetrapeptides) were also investigated with regard to chemically bonded stationary phases for LC. (springer.com)
  • Overall good nutrition is important as well, since sub-optimal vitamin and mineral status can interfere with the synthesis of nonessential amino acids by impairing enzymes or other cofactors involved in the reaction. (52.52.137)
  • For this reason, there is need to understand why amino acids are important, how they are broken down by enzymes, their benefits, and side effects. (dietspotlight.com)
  • Several mechanisms can give rise to analog resistance, but most recovered variants appear to possess altered amino acid levels caused by changes in regulatory enzymes resulting in relaxed feed back control (1, 2). (springer.com)
  • Also known as fatty Acids) are a nutrient that gives us energy, insulates us from the cold, protects our nerves and cushions our organs against impact. (freewebs.com)
  • April 4th - New research led by Harvard T.H. Chan School of Public Health has identified numerous genes that influence how cells respond to saturated fatty acids. (harvard.edu)
  • Examples: oils, fatty acids (i.e. the 'tails' of phospholipids), cholesterol. (wikibooks.org)
  • Fatty acids and their structure. (unimi.it)
  • Catabolism and biosynthesis of fatty acids. (unimi.it)
  • Name, Abbreviations, Chemical classification, Relative Abundance, and Acid-Base properties of each of the natural amino acidsAmino acid. (genosphere-biotech.com)
  • The distinguishing characteristic of each amino acid is a portion of its structure called a side chain or R-group, which has a unique chemical arrangement. (livestrong.com)
  • In addition, each amino acid contains a unique side group that features an element or chemical structure which imparts a specific characteristic or function to that amino acid. (52.52.137)
  • The performed research assisted in the evaluation of the relation between the chemical properties of bonded amino acid sequence and their role in the retention mechanism. (springer.com)
  • Lewis considered this as a generalization of the Brønsted definition, so that an acid is a chemical species that accepts electron pairs either directly or by releasing protons (H + ) into the solution, which then accept electron pairs. (wikipedia.org)
  • Modern definitions are concerned with the fundamental chemical reactions common to all acids. (wikipedia.org)
  • Chemical structures of the 20 standard amino acids. (newworldencyclopedia.org)
  • In enzymology, an L-amino acid oxidase (LAAO) (EC 1.4.3.2) is an enzyme that catalyzes the chemical reaction an L-amino acid + H2O + O2 ⇌ {\displaystyle \rightleftharpoons } a 2-oxo acid + NH3 + H2O2 The enzyme was first described in 1944 by A. Zeller and A. Maritz. (wikipedia.org)
  • Although chemical labeling methods such as ICAT (isotope-coded affinity tags) have demonstrated widespread applicability ( 1 ), metabolic incorporation strategies such as stable isotope labeling with amino acids in cell culture (SILAC) are becoming more common for cell types that can be grown for extensive periods of time in vitro . (mcponline.org)
  • Though there are numerous advantages for using SILAC-based methods, compared with chemical labeling, a major drawback is the unintended metabolic inter-conversion of isotopic amino acids in the labeling process, generating artifacts affecting the quantification. (mcponline.org)
  • This study will evaluate the branched-chain amino acids (BCAA) ratio in the medical foods formulated for Methylmalonic and Propionic Acidemias (MMA/PROP) patients. (clinicaltrials.gov)
  • 6 different ratios of the Branched-chain Amino Acids (BCAA) will be tested for 8 hours each. (clinicaltrials.gov)
  • Your nonessential amino acids are the amino acids your body can create on its own as a byproduct of normal functioning. (aminoco.com)
  • While in theory, we could function perfectly well without any dietary intake of nonessential amino acids, we are actually much more metabolically efficient if we have some percentage of these amino acids supplied by the diet. (52.52.137)
  • For example, with an illness or a catabolic disease , having an abundance of all amino acids facilitates immune system function by ensuring all the amino acid components are available and energy does not need to be devoted to synthesizing nonessential amino acids. (52.52.137)
  • PROLINE is major amino acid found in cartilage and is important for maintaining youthful skin as well as repair of muscle, connective tissue and skin damage. (forresthealth.com)
  • A word familiar to all fans of science fiction , mutation refers to any sudden change in DNA - deoxyribonucleic acid, the genetic blueprint for an organism - that creates a change in an organism's appearance, behavior, or health. (encyclopedia.com)
  • It would have looked unlike any life as we know it today, more basic even than bacterial cells - barely more than a few genetic molecules packaged up in some kind of a sac. (newscientist.com)