Enzyme Stability
Protein Denaturation
Mutagenesis, Site-Directed
Catalysis
Temperature
Models, Molecular
Mutation
Protein Conformation
Molecular Sequence Data
Amino Acid Sequence
Protein Stability
Hydrogen-Ion Concentration
Escherichia coli
RNA Stability
Thermodynamics
Factor XIII Deficiency
Factor XIII
SMN Complex Proteins
Hemostasis
Argon Plasma Coagulation
Phe161 and Arg166 variants of p-hydroxybenzoate hydroxylase. Implications for NADPH recognition and structural stability. (1/5593)
Phe161 and Arg166 of p-hydroxybenzoate hydroxylase from Pseudomonas fluorescens belong to a newly discovered sequence motif in flavoprotein hydroxylases with a putative dual function in FAD and NADPH binding [1]. To study their role in more detail, Phe161 and Arg166 were selectively changed by site-directed mutagenesis. F161A and F161G are catalytically competent enzymes having a rather poor affinity for NADPH. The catalytic properties of R166K are similar to those of the native enzyme. R166S and R166E show impaired NADPH binding and R166E has lost the ability to bind FAD. The crystal structure of substrate complexed F161A at 2.2 A is indistinguishable from the native enzyme, except for small changes at the site of mutation. The crystal structure of substrate complexed R166S at 2.0 A revealed that Arg166 is important for providing an intimate contact between the FAD binding domain and a long excursion of the substrate binding domain. It is proposed that this interaction is essential for structural stability and for the recognition of the pyrophosphate moiety of NADPH. (+info)Properties and regulation of human spermidine/spermine N1-acetyltransferase stably expressed in Chinese hamster ovary cells. (2/5593)
Spermidine/spermine N1-acetyltransferase (SSAT) appears to be the rate-limiting enzyme of polyamine catabolism, yet studies of its regulation have been limited by the low amounts of SSAT in uninduced cells. A system for studying SSAT was established by stably transfecting Chinese hamster ovary cells with a construct where SSAT cDNA was under control of the cytomegalovirus promoter. Thirteen of 44 clones expressed significantly increased SSAT activity (650-1900 compared with 24 pmol/min/mg protein in control cells). SSAT activity was directly proportional to SSAT protein, which turned over very rapidly (t(1)/(2) of 29 min) and was degraded through the ubiquitin/proteasomal pathway. The increased SSAT activity caused perturbations in polyamine homeostasis and led to a reduction in the rate of growth under clonal conditions. N1,N12-bis(ethyl)spermine greatly increased SSAT activity in controls and SSAT transfected clones (to about 10 and 60 nmol/min/mg protein, respectively). N1, N12-Bis(ethyl)spermine caused an increase in the SSAT half-life and a slight increase in SSAT mRNA, but these changes were insufficient to account for the increase in SSAT protein suggesting that translational regulation of SSAT must also occur. (+info)Stabilization from autoproteolysis and kinetic characterization of the human T-cell leukemia virus type 1 proteinase. (3/5593)
We have developed a system for expression and purification of wild-type human T-cell leukemia virus type 1 (HTLV-1) proteinase to attain sufficient quantities for structural, kinetic, and biophysical investigations. However, similar to the human immunodeficiency virus type 1 (HIV-1) proteinase, HTLV-1 proteinase also undergoes autoproteolysis rapidly upon renaturation to produce two products. The site of this autoproteolytic cleavage was mapped, and a resistant HTLV-1 proteinase construct (L40I) as well as another construct, wherein the two cysteine residues were exchanged to alanines, were expressed and purified. Oligopeptide substrates representing the naturally occurring cleavage sites in HTLV-1 were good substrates of the HTLV-1 proteinase. The kinetic parameters kcat and Km were nearly identical for all the three enzymes. Although three of four peptides representing HTLV-1 proteinase cleavage sites were fairly good substrates of HIV-1 proteinase, only two of nine peptides representing HIV-1 proteinase cleavage sites were hydrolyzed by the HTLV-1 proteinase, suggesting substantial differences in the specificity of the two enzymes. The large difference in the specificity of the two enzymes was also demonstrated by inhibition studies. Of the several inhibitors of HIV-1 or other retroviral proteinases that were tested on HTLV-1 proteinase, only two inhibit the enzyme with a Ki lower than 100 nM. (+info)Low temperature cycled PCR protocol for Klenow fragment of DNA polymerase I in the presence of proline. (4/5593)
A method for performing cycled PCR at low temperatures, using the thermolabile Klenow fragment of DNA polymerase I, is reported. Application of proline as a buffer additive in the range of 3.0-5.5 M remarkably increases the thermal stability of the polymerase and decreases the denaturation temperature of DNAtemplate. This method might be applicable to a broad spectrum of thermolabile DNA polymerases in cycled PCR and other methods of DNA amplification. (+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. (5/5593)
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)Molecular cloning, sequencing, and expression of a novel multidomain mannanase gene from Thermoanaerobacterium polysaccharolyticum. (6/5593)
The manA gene of Thermoanaerobacterium polysaccharolyticum was cloned in Escherichia coli. The open reading frame of manA is composed of 3,291 bases and codes for a preprotein of 1,097 amino acids with an estimated molecular mass of 119,627 Da. The start codon is preceded by a strong putative ribosome binding site (TAAGGCGGTG) and a putative -35 (TTCGC) and -10 (TAAAAT) promoter sequence. The ManA of T. polysaccharolyticum is a modular protein. Sequence comparison and biochemical analyses demonstrate the presence of an N-terminal leader peptide, and three other domains in the following order: a putative mannanase-cellulase catalytic domain, cellulose binding domains 1 (CBD1) and CBD2, and a surface-layer-like protein region (SLH-1, SLH-2, and SLH-3). The CBD domains show no sequence homology to any cellulose binding domain yet reported, hence suggesting a novel CBD. The duplicated CBDs, which lack a disulfide bridge, exhibit 69% identity, and their deletion resulted in both failure to bind to cellulose and an apparent loss of carboxymethyl cellulase and mannanase activities. At the C-terminal region of the gene are three repeats of 59, 67, and 56 amino acids which are homologous to conserved sequences found in the S-layer-associated regions within the xylanases and cellulases of thermophilic members of the Bacillus-Clostridium cluster. The ManA of T. polysaccharolyticum, besides being an extremely active enzyme, is the only mannanase gene cloned which shows this domain structure. (+info)A cold-active glucanase from the ruminal bacterium Fibrobacter succinogenes S85. (7/5593)
We previously characterized two endoglucanases, CelG and EGD, from the mesophilic ruminal anaerobe Fibrobacter succinogenes S85. Further comparative experiments have shown that CelG is a cold-active enzyme whose catalytic properties are superior to those of several other intensively studied cold-active enzymes. It has a lower temperature optimum, of 25 degrees C, and retains about 70% of its maximum activity at 0 degrees C, while EGD has a temperature optimum of 35 degrees C and retains only about 18% of its maximal activity at 0 degrees C. When assayed at 4 degrees C, CelG exhibits a 33-fold-higher kcat value and a 73-fold-higher physiological efficiency (kcat/Km) than EGD. CelG has a low thermal stability, as indicated by the effect of temperature on its activity and secondary structure. The presence of small amino acids around the putative catalytic residues may add to the flexibility of the enzyme, thereby increasing its activity at cold temperatures. Its activity is modulated by sodium chloride, with an increase of over 1.8-fold at an ionic strength of 0.03. Possible explanations for the presence of a cold-active enzyme in a mesophile are that cold-active enzymes are more broadly distributed than previously expected, that lateral transfer of the gene from a psychrophile occurred, or that F. succinogenes originated from the marine environment. (+info)Purification and characterization of a novel peroxidase from Geotrichum candidum dec 1 involved in decolorization of dyes. (8/5593)
A peroxidase (DyP) involved in the decolorization of dyes and produced by the fungus strain Geotrichum candidum Dec 1 was purified. DyP, a glycoprotein, is glycosylated with N-acetylglucosamine and mannose (17%) and has a molecular mass of 60 kDa and an isoelectric point (pI) of 3.8. The absorption spectrum of DyP exhibited a Soret band at 406 nm corresponding to a hemoprotein, and its Na2S2O4-reduced form revealed a peak at 556 nm that indicates the presence of a protoheme as its prosthetic group. Nine of the 21 types of dyes that were decolorized by Dec 1 cells were decolorized by DyP; in particular, anthraquinone dyes were highly decolorized. DyP also oxidized 2,6-dimethoxyphenol and guaiacol but not veratryl alcohol. The optimal temperature for DyP activity was 30 degrees C, and DyP activity was stable even after incubation at 50 degrees C for 11 h. (+info)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.
In a medical context, "hot temperature" is not a standard medical term with a specific definition. However, it is often used in relation to fever, which is a common symptom of illness. A fever is typically defined as a body temperature that is higher than normal, usually above 38°C (100.4°F) for adults and above 37.5-38°C (99.5-101.3°F) for children, depending on the source.
Therefore, when a medical professional talks about "hot temperature," they may be referring to a body temperature that is higher than normal due to fever or other causes. It's important to note that a high environmental temperature can also contribute to an elevated body temperature, so it's essential to consider both the body temperature and the environmental temperature when assessing a patient's condition.
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.
Protein denaturation is a process in which the native structure of a protein is altered, leading to loss of its biological activity. This can be caused by various factors such as changes in temperature, pH, or exposure to chemicals or radiation. The three-dimensional shape of a protein is crucial for its function, and denaturation causes the protein to lose this shape, resulting in impaired or complete loss of function. Denaturation is often irreversible and can lead to the aggregation of proteins, which can have negative effects on cellular function and can contribute to diseases such as Alzheimer's and Parkinson's.
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.
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.
Temperature, in a medical context, is a measure of the degree of hotness or coldness of a body or environment. It is usually measured using a thermometer and reported in degrees Celsius (°C), degrees Fahrenheit (°F), or kelvin (K). In the human body, normal core temperature ranges from about 36.5-37.5°C (97.7-99.5°F) when measured rectally, and can vary slightly depending on factors such as time of day, physical activity, and menstrual cycle. Elevated body temperature is a common sign of infection or inflammation, while abnormally low body temperature can indicate hypothermia or other medical conditions.
Drug stability refers to the ability of a pharmaceutical drug product to maintain its physical, chemical, and biological properties during storage and use, under specified conditions. A stable drug product retains its desired quality, purity, strength, and performance throughout its shelf life. Factors that can affect drug stability include temperature, humidity, light exposure, and container compatibility. Maintaining drug stability is crucial to ensure the safety and efficacy of medications for patients.
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 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.
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 α-helices and β-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.
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.
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.
Protein stability refers to the ability of a protein to maintain its native structure and function under various physiological conditions. It is determined by the balance between forces that promote a stable conformation, such as intramolecular interactions (hydrogen bonds, van der Waals forces, and hydrophobic effects), and those that destabilize it, such as thermal motion, chemical denaturation, and environmental factors like pH and salt concentration. A protein with high stability is more resistant to changes in its structure and function, even under harsh conditions, while a protein with low stability is more prone to unfolding or aggregation, which can lead to loss of function or disease states, such as protein misfolding diseases.
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.
'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.
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.
RNA stability refers to the duration that a ribonucleic acid (RNA) molecule remains intact and functional within a cell before it is degraded or broken down into its component nucleotides. Various factors can influence RNA stability, including:
1. Primary sequence: Certain sequences in the RNA molecule may be more susceptible to degradation by ribonucleases (RNases), enzymes that break down RNA.
2. Secondary structure: The formation of stable secondary structures, such as hairpins or stem-loop structures, can protect RNA from degradation.
3. Presence of RNA-binding proteins: Proteins that bind to RNA can either stabilize or destabilize the RNA molecule, depending on the type and location of the protein-RNA interaction.
4. Chemical modifications: Modifications to the RNA nucleotides, such as methylation, can increase RNA stability by preventing degradation.
5. Subcellular localization: The subcellular location of an RNA molecule can affect its stability, with some locations providing more protection from ribonucleases than others.
6. Cellular conditions: Changes in cellular conditions, such as pH or temperature, can also impact RNA stability.
Understanding RNA stability is important for understanding gene regulation and the function of non-coding RNAs, as well as for developing RNA-based therapeutic strategies.
I'm sorry for any confusion, but "thermodynamics" is not a term that has a specific medical definition. It is a branch of physics that deals with the relationships between heat and other forms of energy. However, the principles of thermodynamics can be applied to biological systems, including those in the human body, such as in the study of metabolism or muscle function. But in a medical context, "thermodynamics" would not be a term used independently as a diagnosis, treatment, or any medical condition.
Factor XIII deficiency, also known as fibrin stabilizing factor deficiency, is a rare bleeding disorder caused by a lack or dysfunction of Factor XIII, a protein involved in the final stage of blood clotting. This deficiency results in impaired clot stability and increased risk of bleeding. Symptoms can include umbilical cord bleeding at birth, prolonged bleeding after circumcision, easy bruising, nosebleeds, muscle bleeds, gastrointestinal bleeds, and excessive menstrual bleeding. Treatment typically involves replacement of the missing Factor XIII through injections, either prophylactically or on-demand to manage bleeding episodes.
Factor XIII, also known as fibrin stabilizing factor, is a protein involved in the clotting process of blood. It is a transglutaminase enzyme that cross-links fibrin molecules to form a stable clot. Factor XIII becomes activated during the coagulation cascade, and its activity helps strengthen the clot and protect it from premature degradation by proteolytic enzymes. A deficiency in Factor XIII can lead to a bleeding disorder characterized by prolonged bleeding after injury or surgery.
The Survival Motor Neuron (SMN) complex is a protein complex that plays a crucial role in the biogenesis of small nuclear ribonucleoproteins (snRNPs), which are essential components of the spliceosome involved in pre-messenger RNA (pre-mRNA) splicing. The SMN complex consists of several proteins, including the SMN protein itself, Gemins2-8, and unrip.
The SMN protein is the central component of the complex and is encoded by the SMN1 gene located on chromosome 5q13.2. Mutations in this gene can lead to spinal muscular atrophy (SMA), a genetic disorder characterized by degeneration of motor neurons in the spinal cord, leading to muscle weakness and atrophy.
The SMN complex assembles in the cytoplasm and facilitates the assembly of spliceosomal snRNPs by helping to load Sm proteins onto small nuclear RNA (snRNA) molecules. Proper functioning of the SMN complex is essential for the correct splicing of pre-mRNA, and its dysfunction can lead to various developmental abnormalities and diseases, including SMA.
Hemostasis is the physiological process that occurs to stop bleeding (bleeding control) when a blood vessel is damaged. This involves the interaction of platelets, vasoconstriction, and blood clotting factors leading to the formation of a clot. The ultimate goal of hemostasis is to maintain the integrity of the vascular system while preventing excessive blood loss.
Argon Plasma Coagulation (APC) is a medical procedure that uses ionized argon gas to deliver electrical current and heat to tissue, resulting in coagulation. It is commonly used in the treatment of gastrointestinal bleeding, as well as for cutting and coagulating during surgical procedures. The argon plasma is created by passing argon gas through a high-voltage electrical field, which ionizes the gas and creates a highly precise and controllable plasma beam. This beam can be directed at the tissue to achieve hemostasis (stopping bleeding) or to cut tissue with minimal thermal damage to surrounding structures. The procedure is often performed under endoscopic guidance.
Blood coagulation, also known as blood clotting, is a complex process that occurs in the body to prevent excessive bleeding when a blood vessel is damaged. This process involves several different proteins and chemical reactions that ultimately lead to the formation of a clot.
The coagulation cascade is initiated when blood comes into contact with tissue factor, which is exposed after damage to the blood vessel wall. This triggers a series of enzymatic reactions that activate clotting factors, leading to the formation of a fibrin clot. Fibrin is a protein that forms a mesh-like structure that traps platelets and red blood cells to form a stable clot.
Once the bleeding has stopped, the coagulation process is regulated and inhibited to prevent excessive clotting. The fibrinolytic system degrades the clot over time, allowing for the restoration of normal blood flow.
Abnormalities in the blood coagulation process can lead to bleeding disorders or thrombotic disorders such as deep vein thrombosis and pulmonary embolism.
Enzyme promiscuity
Industrial enzymes
Muconate lactonizing enzyme
Immobilized enzyme
Enzyme assay
Acyl-CoA dehydrogenase
Cross-linked enzyme aggregate
Monocerin
Barnase
Alan J. Russell
Nanoparticle-biomolecule conjugate
Cyclin-dependent kinase 2
P53
Capping enzyme
Nanogel
Biosensor
Inhibitor cystine knot
Surface plasmon resonance microscopy
N-glycosyltransferase
Factor XIII
Nepenthesin
Evolvability
Flucloxacillin
S-Adenosylmethionine synthetase enzyme
Polaribacter
Shelley D. Minteer
Discovery and development of dipeptidyl peptidase-4 inhibitors
Tretinoin
Cold hardening
Formylglycine-generating enzyme
PRIME PubMed | Tyrosine residue 300 is important for activity and stability of branching enzyme from Escherichia coli
"The Relationship of Lysosomal Stability and Plasma Enzyme Levels To St" by Michael L. Bonin
regression - Which statistical method should be used in the study of stability of an enzyme? - Cross Validated
Relationship between structure and stability in the active site of bacterial Enzyme I
Angiotensin Converting Enzyme (ACE) (683) | Rady Children's Hospital
Catalysts | Free Full-Text | Study of Prepared α-Chymotrypsin as Enzyme Nanoparticles and of Biocatalytic Membrane Reactor
MMP-3 Enzyme Human | Matrix Metallopeptidase 3 | ProSpec
NUDT21 Enzyme Human Recombinant | Nudix Hydrolase 21 | ProSpec
CICECO Publication » Laccase recovery with aqueous two-phase systems: Enzyme partitioning and stability
Preparation of enzyme-in-polymer composites with high activity and stability<...
Effect of liquid digestate recirculation on biogas production and enzyme activities for anaerobic digestion of corn straw |...
Three pairs of surrogate redox partners comparison for Class I cytochrome P450 enzyme activity reconstitution | Communications...
Enzyme promiscuity - Wikipedia
Parkinson's Progression Halted by Inhibiting Enzyme - Neuroscience News
Xylazyme Tablets | Enzyme Activity Analysis | Neogen
Immobilization of Lipases on Heterofunctional Octyl-Glyoxyl Agarose Supports: Improved Stability and Prevention of the Enzyme...
Exceptional thermal stability of therapeutical enzymes entrapped in alumina sol-gel matrices | SCAMT
Red Wine Color Stability - WineMakerMag.com
ATF7IP-Mediated Stabilization of the Histone Methyltransferase SETDB1 Is Essential for Heterochromatin Formation by the HUSH...
Angiotensin I Converting Enzyme 2 (ACE-2) Inhibitor, DX 600 - 0.1 mg
Homology modeling reveals the structural background of the striking difference in thermal stability between two related [NiFe...
Mouse Study Finds That Mutant Enzyme is Able to Help Protect DNA From Damage | National Institutes of Health (NIH)
99 questions with answers in ANTIOXIDANT ENZYMES | Science topic
1.18.1.2: ferredoxin-NADP+ reductase - BRENDA Enzyme Database
1.1.1.105: all-trans-retinol dehydrogenase (NAD+) - BRENDA Enzyme Database
PriceGrabber - Kyolic kyo dophilus probiotics plus cranberry, Probiotics, 501milligrams & More Vitamins & Nutrition
Scientists figured out how to replace enzymes | EurekAlert!
Factor XIII Deficiency: Practice Essentials, Background, Pathophysiology
TGM5 gene: MedlinePlus Genetics
Catalysts | Free Full-Text | Enzymatic Bioelectrocatalysis
Angiotensin Conver1
- Sex differences in angiotensin-converting enzyme modulation of Ang (1-7) levels in normotensive WKY rats. (anaspec.com)
Substrate2
- Enzymes are evolved to catalyse a particular reaction on a particular substrate with a high catalytic efficiency (kcat/KM, cf. (wikipedia.org)
- Based on their intrinsic properties, i.e., high specificity and high affinity for the substrate, enzymes may provide sustainable alternatives to currently used chemical catalysts for human health monitoring, biopower generation or high-value product synthesis. (mdpi.com)
Metabolism4
- Bacterial Enzyme I (EI) is a central regulator of bacterial metabolism and a promising drug target. (growkudos.com)
- 300 enzymes, and in the metabolism of proteins and nucleic acids (WHO 2001). (cdc.gov)
- These studies critically evaluated and characterized the principal enzymes responsible for drug metabolism. (environmentalchemistry.com)
- G6PD deficiency occurs because of a genetic defect in an enzyme involved in red blood cell metabolism. (msdmanuals.com)
Catalysts4
- Although enzymes are remarkably specific catalysts, they can often perform side reactions in addition to their main, native catalytic activity. (wikipedia.org)
- Replacing enzymes with more stable and cheaper oxidation catalysts will reduce the cost of glucometers and extend their shelf life. (eurekalert.org)
- To date, only one method has been developed for direct blood analysis using enzyme-free catalysts based on palladium nanoparticles. (eurekalert.org)
- Thus, scientists are faced with the task of synthesizing enzyme-free catalysts, which will make it possible to more accurately and with lower financial costs determine the concentration of glucose in the blood. (eurekalert.org)
Activity14
- Replacement of Y300 with Ala, Asp, Leu, Ser, and Trp resulted in mutant enzymes with less than 1% of wild-type activity. (unboundmedicine.com)
- Thus, these results show that Tyr residue 300 in E. coli branching enzyme is important for activity and thermostability of the enzyme. (unboundmedicine.com)
- TY - JOUR T1 - Tyrosine residue 300 is important for activity and stability of branching enzyme from Escherichia coli. (unboundmedicine.com)
- Here, a novel method is described to rationally design the support matrix to retain the enzyme on the support matrix without leaching and also activate the enzyme for full activity retention. (bvsalud.org)
- High purity dyed and crosslinked Xylazyme (100 mg tablets) for the measurement of enzyme activity, for research, biochemical enzyme assays and in vitro diagnostic analysis. (neogen.com)
- On the other, enzymes may evolve an increased secondary activity with little loss to the primary activity ("robustness") with little adaptive conflict (§ Robustness and plasticity below). (wikipedia.org)
- This means firstly that a specialist enzyme (monofunctional) when evolved goes through a generalist stage (multifunctional), before becoming a specialist again-presumably after gene duplication according to the IAD model-and secondly that promiscuous activities are more plastic than the main activity. (wikipedia.org)
- Evidence gained from reconstructed enzyme suggests that the order of the events where the novel activity is improved and the gene is duplication is not clear cut, unlike what the theoretical models of gene evolution suggest. (wikipedia.org)
- This exceedingly high stability is seen also with the other two enzymes: thus, when HRP or ASP are heated in solution to 75 °C the activity drops by 65% and 72%, respectively, but when entrapped it drops only by 1.2% and 1.9%, respectively. (ifmo.ru)
- At what concentration does hydrogen peroxide inhibit enzyme activity? (researchgate.net)
- This and other T GM5 gene variants reduce the activity of transglutaminase 5 or prevent cells from making any of this enzyme. (medlineplus.gov)
- Standard protein purification and characterization techniques, enzyme activity assays, as well as immunoassays (ELISA) will also be taught. (uaeu.ac.ae)
- Sodium and proline contents were also measured and finally, effects of MJ and salinity interactions on all characteristics as well as relationship of antioxidant enzymes activity with proline content were investigated. (springer.com)
- With regard to these enzymes (metalloproteinases - MMPs), studies have demonstrated its effect on collagen fibril degradation and indicated the possibility of slowing this process through inhibiting its activity 3,5,15,47,49 . (bvsalud.org)
Proteins4
- Cytochrome P450 enzymes (P450s or CYPs) are a superfamily of heme-thiolate proteins widespread in all kingdoms of life 1 . (nature.com)
- Can someone guide me on the references of spectrophotometer methods used to measure enzymes or proteins newly discovered in the blood serum? (researchgate.net)
- What are the main references (book or research) for one or more, that specify methods for measuring newly discovered enzymes or proteins, in which simple manual methods are used. (researchgate.net)
- Explain The Various Ways That Enzymes Can Be Regulated, Including Post-Translational Modifications Of Proteins And Their Degradation. (uaeu.ac.ae)
Synonyms1
- Synonyms: Enzyme Preparation (Protein). (edocr.com)
Antioxidant enzymes3
- Explore the latest questions and answers in Antioxidant Enzymes, and find Antioxidant Enzymes experts. (researchgate.net)
- Haemoglobin is a serious problem during purification and analysis of antioxidant enzymes from red blood cells. (researchgate.net)
- The aim was to determine whether MJ could protect chamomile production against salinity and whether this protection was associated with regulation of antioxidant enzymes. (springer.com)
Enzymatic1
- Enzymes known as matrix metalloproteinases (MMPs) are responsible by enzymatic degradation of collagen fibrils without protection, which are present in the resin-dentine interface. (bvsalud.org)
Aqueous1
- designed, synthesized, and investigated the effects of a cationic comb polymer on the stability of aqueous silica suspensions of varying ionic strength and pH. (rpi.edu)
Synthesis2
- Trimethoxysilyl and acrylamide-bisacrylamide polymers have been used for synthesis of enzyme nanoparticles. (mdpi.com)
- First proposed in 1963 by Linus Pauling and Emile Zuckerkandl, ancestral reconstruction is the inference and synthesis of a gene from the ancestral form of a group of genes, which has had a recent revival thanks to improved inference techniques and low-cost artificial gene synthesis, resulting in several ancestral enzymes-dubbed "stemzymes" by some-to be studied. (wikipedia.org)
Reproducibility2
- Furthermore, due to the complicated preparation process of EIs and the complexity of the immunoassay, the reproducibility and stability of EI are susceptible. (cdc.gov)
- 3D printing technologies are capable of improving the reproducibility and stability of EI by precise device production processes with fast design-to-object multiplex capabilities and different analytical formats. (cdc.gov)
Catalysis1
- Conformational disorder is emerging as an important feature of enzyme catalysis. (growkudos.com)
Polymer1
- Biocatalytic kinetic effect of α -chymotrypsin enzyme has been investigated in its free and pretreated forms (it was covered by a very thin, porous polymer layer, called enzyme nanoparticle) as well as its immobilized form into pores of polysulfone/polyamide asymmetric, hydrophilic membrane. (mdpi.com)
Helicase4
- Pif1 is a multifunctional helicase and DNA processing enzyme that has roles in genome stability. (rcsb.org)
- However, it was fascinating to find that the mutations caused by quantum tunnelling are more stable due to the action of the enzyme, helicase. (sciencedaily.com)
- While others have painted helicase as a gatekeeper to quantum mutation, our research suggests that the enzyme is deeply intertwined with the formation of these mutations. (sciencedaily.com)
- The strand separation is enabled by a type of enzyme called a 'helicase', which binds to one of the DNA strands and pulls it through itself, thereby forcing apart the DNA. (sciencedaily.com)
Membrane stability1
- The photosynthetic rate concomitantly with membrane stability index, potassium content, as well as free proline content was markedly increased. (springer.com)
Regulation1
- In this work we combine biochemical and biophysical techniques to show how functional regulation of EI is attained by diluting the active enzyme with inactive states. (growkudos.com)
Matrices2
- Subsequent cross-linking of the enzyme with glutaraldehyde resulted in stable entrapped enzyme within the polymeric matrices. (korea.ac.kr)
- Alumina sol-gel matrices emerge in this study as very interesting biocompatible superior materials for entrapment and stabilization of enzymes. (ifmo.ru)
Genetic2
- Enzymes, which are crucial to controlling how cells replicate in the human body, could be the very ingredient that encourages DNA to spontaneously mutate -- causing potentially permanent genetic errors, according to new research. (sciencedaily.com)
- This famous double helix structure gives DNA its remarkable stability, along with its pairing rules between the genetic letters on opposite strands. (sciencedaily.com)
Metabolic2
- BRENDA, enzyme data and metabolic information. (brenda-enzymes.org)
- BRENDA: a resource for enzyme data and metabolic information. (brenda-enzymes.org)
Biochemical1
- In this work we use biophysical (NMR, crystallography, MD simulations) and biochemical (enzymology, protein engineering) techniques to show how bacterial Enzyme I is thermodynamically regulated by structural heterogeneity in the active site. (growkudos.com)
Long-term stab1
- Bioelectrocatalysis is also limited by long-term stability requiring groundbreaking strategies for enzyme protection and bioelectrode survival. (mdpi.com)
Mechanisms3
- Yet despite the rapid advances in the clinical application of diagnostic enzymology, little is known about the basic mechanisms responsible for the enzyme perturbations measured. (marquette.edu)
- Although enzyme mechanisms may differ between humans and mice, gaining a better understanding of DNA damage repair might someday allow us to specifically alter ATM in cancer cells. (nih.gov)
- However, enzyme bioelectrocatalysis suffers from low catalytic efficiency, imposing fundamental investigations on mechanisms of enzyme immobilization, including molecular basis knowledge of the efficient electronic communication between enzymes and the electrode. (mdpi.com)
Preparation1
- Preparation of this useful support and enzyme immobilization on it via covalent linking is described here. (bvsalud.org)
Kinetic1
- BRENDA in 2013: integrated reactions, kinetic data, enzyme function data, improved disease classification: new options and contents in BRENDA. (brenda-enzymes.org)
Variants1
- In most KPC-endemic regions, including United States and countries in Europe, KPC-3 showed similar prevalence as that of KPC-2 enzyme, and both KPC variants were frequently detected in clinical CRE isolates. (cdc.gov)
Digestive2
- The above digestive enzymes. (pricegrabber.com)
- Feeds for broilers are formulated almost exclusively with ingredients of plant origin, which mostly contain anti-nutritional compounds, as these animals do not produce enzymes capable of digesting these compounds in their digestive systems. (scielo.br)
Molecular1
- Enzymes were codissolved in toluene with commercial, high-molecular-weight polymers, and the solvent was then rapidly removed by injecting the mixture into a vacuum chamber. (korea.ac.kr)
Gene4
- In a mouse model engineered to lack the gene that produces the enzyme-known as a "knockout model" because one specific gene has been deleted for the purposes of experimentation-the researchers observed that the loss of USP30 protected against the development of Parkinson's-like motor symptoms, increased clearance of damaged mitochondria in neurons, and protected against the loss of dopamine-producing neurons. (neurosciencenews.com)
- The TGM5 gene provides instructions for making an enzyme called transglutaminase 5. (medlineplus.gov)
- People who have G6PD deficiency inherit a defect in the gene responsible for producing G6PD so they do not have enough of the enzyme in their blood cells. (msdmanuals.com)
- The most commonly reported adverse reactions of the gene therapy include vomiting, nausea, increases in liver enzymes, pyrexia (fever), and thrombocytopenia, all of which occurred within 90 days of infusion and been manageable. (medscape.com)
Immobilization2
- Immobilization of Lipases on Heterofunctional Octyl-Glyoxyl Agarose Supports: Improved Stability and Prevention of the Enzyme Desorption. (bvsalud.org)
- It couples the numerous advantages of the octyl- agarose support to covalent immobilization and creates the possibility of using the biocatalyst under any experimental conditions without risk of enzyme desorption and leaching . (bvsalud.org)
Shelf life1
- Since enzymes are of a protein nature, they denaturate under heat or light exposure, and their shelf life is limited. (eurekalert.org)
Susceptible1
- EMERGENCY OVERVIEW: POTENTIAL HEALTH EFFECTS Inhalation of enzyme aerosol by susceptible individuals may result in allergic sensitization. (edocr.com)
Temperature6
- MMP-3 enzyme is also known as Stromelysin-1or as Transin-1 which hydrolyzes natural collagen at physiological pH and temperature. (prospecbio.com)
- Additionally, for the first time, laccase stability in different ATPS was investigated by incubating the enzyme in each equilibrium phase during a week, at room temperature. (ua.pt)
- However, lipase molecules may be released from the support under certain conditions (high temperature , organic solvents ), as there are no covalent links between the enzyme and the support matrix. (bvsalud.org)
- The results are in accord with the general observation that with increasing temperature, the role of electrostatic interactions in protein stability increases. (nih.gov)
- Guaranteed stability at room temperature. (pricegrabber.com)
- The extent of enzyme inactivation increased with pressure (600-800 MPa) and temperature (30-70 °C) for all the mustard seeds. (reading.ac.uk)
Processes2
- Through the measurement of vast numbers of enzymes and isoenzymes, in blood and various other body fluids, a relatively non-invasive method exists for making organ specific diagnosis of various pathologic processes including infarction, inflammation, and tumor invasion as examples. (marquette.edu)
- Study of the problem requires investigation of fundamental cell physiology and pathologic alterations of the physiologic processes, while the data generated provides answers to existing clinical situations and opens new avenue for clinical application of enzyme interpretation. (marquette.edu)
Functional1
- By using functional nanomaterial s, a DNA/enzyme amplification approach, and new electroanalytical techniques, EIs are both sensitive and selective, especially in the simplification and miniaturization of devices, making them ideally suitable for POC diagnosis. (cdc.gov)
Newly1
- However, using extant enzymes to determine how the family of enzymes evolved has the drawback that the newly evolved enzyme is compared to paralogues without knowing the true identity of the ancestor before the two genes diverged. (wikipedia.org)
Coli2
- In Escherichia coli branching enzyme, this residue (Y300) is located prior to the conserved region 1. (unboundmedicine.com)
- Site-directed mutagenesis of the Y300 residue in E. coli branching enzyme was used in order to study its possible function in branching enzymes. (unboundmedicine.com)
Differ1
- Two homologous nickel-iron hydrogenases, HupSL and HydSL from the photosynthetic purple sulfur bacterium Thiocapsa roseopersicina, differ substantially in their thermal stabilities despite the high sequence similarity between them. (nih.gov)
Analysis3
- Analysis of these glycans can be accomplished with the use of deglycosylation enzymes, which can provide complete sugar removal with no protein degradation. (neb.com)
- Computational modeling of protein mutant stability: analysis and optimization of statistical potentials and structural features reveal insights into prediction model development. (brenda-enzymes.org)
- Structural Analysis and Prediction of Protein Mutant Stability using Distance and Torsion Potentials: Role of Secondary Structure and Solvent Accessibility. (brenda-enzymes.org)
Thermal stability1
- The thermal stability was studied in detail, by the follow-up of kinetics, by differential scanning calorimetry and by circular dichroism. (ifmo.ru)
Protein stability1
- CUPSAT: prediction of protein stability upon point mutations. (brenda-enzymes.org)
Role4
- Simon and colleagues focused on an enzyme called USP30 which plays a role in this process. (neurosciencenews.com)
- This enzyme is found in many of the body's tissues, although it seems to play a key role in the outer layer of skin (the epidermis). (medlineplus.gov)
- Describe the kinetics, mechanism and role of enzymes in living systems. (uaeu.ac.ae)
- Our data are in agreement with a role for Nt-acetylation in promoting stability for parts of the proteome by enhancing the avidity of protein-protein interactions and folding. (lu.se)
Cells2
- This dissertation investigated the possibility that loss of lysosomal integrity may be the inciting event for release of enzymes from cells. (marquette.edu)
- The addition of phosphate groups is a common mechanism used by cells to turn enzymes on and off. (nih.gov)
Significantly2
- The heat stability of Y300F was analyzed, and this was lowered significantly compared to that of the wild-type enzyme. (unboundmedicine.com)
- Moreover, the application of the investigated 75 μM MJ significantly improved enzyme activities in terms of catalase, peroxidase and ascorbate peroxidase activities. (springer.com)
Conformational1
- A more optimized cavity system and amino acid replacements resulting in increased conformational rigidity may also contribute to the higher stability of HydSL. (nih.gov)
Blood3
- The new system, the developers say, can be used to create an enzyme-free electrocatalytic sensor for determining glucose in whole blood. (eurekalert.org)
- Enzymes are fixed on the working sensitive part of the test strip (sensor), where a drop of blood is fed. (eurekalert.org)
- A blood test can assess the level of the G6PD enzyme. (msdmanuals.com)
Occurs1
- Research has shown that when DNA damage occurs, a key enzyme - called ataxia telangiectasia mutated protein, or ATM - becomes activated. (nih.gov)
Clinical1
- Performed research and development of proprietary lipid delivery-systems through formulation, stability, and pre-clinical pharmacokinetic/pharmacodynamic studies. (environmentalchemistry.com)
Matrix1
- The conditions are described to increase the possibility of achieving at least one covalent attachment between each enzyme molecule and the support matrix. (bvsalud.org)
Process4
- While other deranged cellular events may also participate in the process, it was anticipated that the results obtained would provide an initial unifying concept concerning the mechanism responsible for enzyme release. (marquette.edu)
- If I were in charge of some process that used enzymes (DNA sequencing, fruit peeling, whatever), I don't think I'd be terribly surprised to learn that enzymes degrade over time. (stackexchange.com)
- Several theoretical models exist to predict the order of duplication and specialisation events, but the actual process is more intertwined and fuzzy (§ Reconstructed enzymes below). (wikipedia.org)
- ATM's activation was believed to involve a process called autophosphorylation, in which the enzyme would add a phosphate group to itself and then be released from an inactive state. (nih.gov)
Results1
- The best stability results were obtained with PEG-sulfate salts. (ua.pt)
Main2
- Enzyme promiscuity is the ability of an enzyme to catalyse a fortuitous side reaction in addition to its main reaction. (wikipedia.org)
- The main enzyme responsible for Nt-acetylation throughout the eukaryotic kingdom is the N-terminal acetyltransferase NatA. (lu.se)
Function2
- A new study in mice shows that this enzyme continues to be activated and function normally, even without a chemical modification previously thought to be necessary. (nih.gov)
- EnzymeDetector: an integrated enzyme function prediction tool and database. (brenda-enzymes.org)
Important2
- From the nutrition point of view, the technical feasibility of exogenous enzymes can be seen as an important milestone, as it allows better use of nutrients. (scielo.br)
- G6PD is an enzyme important for maintaining the stability of hemoglobin. (msdmanuals.com)