NationMaster - Encyclopedia: Protease

Proteases (proteinases, peptidases, or proteolytic enzymes) are enzymes that break peptide bonds between amino acids of proteins. The process is called peptide cleavage, a common mechanism of activation or inactivation of enzymes, especially those involved in blood coagulation or digestion. They use a molecule of water for this and are thus classified as hydrolases. Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... A peptide bond is a chemical bond formed between two molecules when the carboxyl group of one molecule reacts with the amino group of the other molecule, releasing a molecule of water (H2O). ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... In chemistry, a molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical bonds [1] [2] [3] [4] [5]. Chemical substances are not infinitely divisible into smaller fractions of the same substance: a molecule is generally considered the smallest particle of a pure... Impact of a drop of water. ... In biochemistry, a hydrolase is an enzyme that can break a chemical bond by hydrolysis. ...

Classification

There are currently six classes of proteases: 2004 is a leap year starting on Thursday of the Gregorian calendar. ...

The threonine and glutamic acid proteases were not described until 1995 and 2004, respectively. The mechanism used to cleave a peptide bond involves making an amino acid residue that has the character of a polarized peptide bond (serine, cysteine and threonine peptidases) or a water molecule (aspartic acid, metallo- and glutamic acid peptidases) nucleophilic so that it can attack the peptide carbonyl group. One way to make a nucleophile is by a catalytic triad, where a histidine residue is used to activate serine, cysteine or threonine as a nucleophile. Crystal structure of Trypsin, a typical serine protease. ... Proteases are enzymes that degrade polypeptides. ... Aspartic acid Aspartic acid proteases are protease enzymes which have an aspartic acid residue in the active site of the enzyme. ... Plasmepsins are a class of at least 10 enzymes produced by the plasmodium parasite. ... The metalloendopeptidases (also called metalloproteinases or metalloproteases) are a class of enzymes from the group of endopeptidases. ... 1995 (MCMXCV) was a common year starting on Sunday of the Gregorian calendar. ... 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Carbonyl group In organic chemistry, a carbonyl group is a functional group composed of a carbon atom double-bonded to an oxygen atom. ... Three amino acid residues found inside the active site of certain proteases. ... Histidine is one of the 20 most common natural amino acids present in proteins. ... Serine is one of the 20 natural amino acids. ... Cysteine is a naturally occurring amino acid which has a thiol group and is found in most proteins, though only in small quantities. ... Threonine is one of the 20 natural amino acids. ...

Occurrence

Proteases occur naturally in all organisms and constitute 1-5% of the gene content. These enzymes are involved in a multitude of physiological reactions from simple digestion of food proteins to highly regulated cascades (e.g., the blood clotting cascade, the complement system, apoptosis pathways, and the invertebrate prophenoloxidase activating cascade). Peptidases can break either specific peptide bonds (limited proteolysis), depending on the amino acid sequence of a protein, or break down a complete peptide to amino acids (unlimited proteolysis). The activity can be a destructive change abolishing a protein's function or digesting it to its principal components; it can be an activation of a function or it can be a signal in a signalling pathway. The coagulation of blood is a complex process during which blood forms solid clots. ... A complement protein attacking an invader. ... A cell undergoing apoptosis. ... Phenylalanine is one of the standard amino acids. ...

Proteases are also a type of exotoxin, which is a virulence factor in bacteria pathogenesis. Bacteria exotoxic proteases destroy extracellular structures.

Inhibitors

The function of peptidases is inhibited by protease inhibitor enzymes. Examples of protease inhibitors are the class of serpins (serine protease or peptidase inhibitors), incorporating alpha 1-antitrypsin. Other serpins are complement 1-inhibitor, antithrombin, alpha 1-antichymotrypsin, plasminogen activator inhibitor 1 (coagulation, fibrinolysis) and the recently discovered neuroserpin. In biology and biochemistry, protease inhibitors are molecules that inhibit the function of peptidases (old name: protease, hence the term protease inhibitor). ... Serpins (short for serine protease inhibitor) are a group of structurally related proteins, many of which inhibit peptidases (enzymes that degrade protein, old name: proteases). ... Alpha 1-antitrypsin or α1-antitrypsin (A1AT) is a serine protease inhibitor (serpin). ... A complement protein attacking an invader. ... Image:Antithrombin. ... Alpha 1-antichymotrypsin is a alpha globulin glycoprotein and serpin. ... Plasminogen activator inhibitor-1 is the principal inhibitor of tissue plasminogen activator (tPA) and urokinase (uPA), the activators of plasminogen and hence fibrinolysis (the physiological breakdown of blood clots). ... The coagulation of blood is a complex process during which blood forms solid clots. ... Fibrinolysis is the process where a fibrin clot, the product of coagulation, is broken down. ...

Natural protease inhibitors include the family of lipocalin proteins, which play a role in cell regulation and differentiation. Lipophilic ligands, attached to lipocalin proteins, have been found to possess tumor protease inhibiting properties. The natural protease inhibitors are not to be confused with the protease inhibitors used in antiretroviral therapy. Some viruses, with HIV among them, depend on proteases in their reproductive cycle. Thus, protease inhibitors are developed as antiviral means. The lipocalin family of proteins is a functionally and structurally diverse group. ... This article or section does not cite its references or sources. ... In biology and biochemistry, protease inhibitors are molecules that inhibit the function of peptidases (old name: protease, hence the term protease inhibitor). ... Protease inhibitors are a class of medication used to treat or prevent viral infections. ... A common alternate meaning of virus is computer virus. ... Human immunodeficiency virus or HIV is a retrovirus that causes Acquired Immunodeficiency Syndrome (AIDS), a condition in which the immune system begins to fail, leading to life-threatening opportunistic infections. ... Protease inhibitors are a class of medication used to treat or prevent viral infections. ... Antiviral drugs are a class of medication used specifically for treating viral infections. ...

Degradation

Proteases, being themselves proteins, are known to be cleaved by other protease molecules, sometimes of the same variety. This may be an important method of regulation of peptidase activity.

Protease research

The field of protease research is enormous. Barrett and Rawlings estimated that approximately 8000 papers related to this field are published each year. For a look at current activities and interests of protease researchers, see the International Proteolysis Society web page.

References

External links

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Proteins: enzymes

Active site - Binding site - Catalytically perfect enzyme - Coenzyme - Cofactor - EC number - Enzyme catalysis - Enzyme kinetics - Enzyme inhibitor - Lineweaver-Burk plot - Michaelis-Menten kinetics Medical Subject Headings (MeSH) is a huge controlled vocabulary (or metadata system) for the purpose of indexing journal articles and books in the life sciences. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... The active site of an enzyme is the binding site where catalysis occurs. ... A binding site is a region on a protein to which specific ligands bind. ... Catalytically perfect enzyme or kineticall perfect enzyme is an enzyme that catalyzes so efficiently, that almost every time enzyme meets its substrate, the reaction occurs. ... Coenzymes are a small organic non-protein molecules that carry chemical groups between enzymes. ... A cofactor is any substance that needs to be present in addition to an enzyme to catalyze a certain reaction. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Enzyme catalysis is the catalysis of chemical reactions by enzyme molecules. ... It has been suggested that this article or section be merged with Enzyme. ... HIV protease in a complex with the protease inhibitor ritonavir. ... In biochemistry, the Lineweaver-Burk plot (or double reciprocal plot) is a graphical representation of the Lineweaver-Burk equation of enzyme kinetics, described by Hans Lineweaver and Dean Burk in 1934. ... Michaelis-Menten kinetics describes the kinetics of many enzymes. ...

EC1 Oxidoreductases/list (catalase, dehydrogenase, hydroxylase, oxygenase, oxidase, peroxidase) - EC2 Transferases/list (methyltransferase, acyltransferase, glycosyltransferase, transaminase, phosphotransferase, polymerase, kinase) - EC3 Hydrolases/list (esterase, DNA glycosylases, glycosidase, protease, helicase) - EC4 Lyases/list (carboxy-lyases, aldolase, dehydratase, synthase) - EC5 Isomerases/list (mutase, topoisomerase) - EC6 Ligases/list (DNA ligase, aminoacyl tRNA synthetase) In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule (the oxidant, also called the hydrogen donor or electron donor) to another (the reductant, also called the hydrogen acceptor or electron acceptor). ... This list contains a list of EC numbers for the first group, EC 1, oxidoreducatases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... Catalase (human erythrocyte catalase: PDB 1DGF, EC 1. ... A dehydrogenase is an enzyme that oxidizes a substrate by transferring one or more protons and a pair of electrons to an acceptor, usually NAD/NADP or a flavin coenzyme such as FAD or FMN. Common examples of dehydrogenase enzymes in the TCA cycle are pyruvate dehydrogenase, isocitrate dehydrogenase, and... Hydroxylation is any chemical process that introduces one or more hydroxyl groups (-OH) into a compound (or radical) thereby oxidising it. ... An oxygenase is any enzyme that oxidizes a substrate by transferring the oxygen from molecular oxygen O2 (as in air) to it. ... An oxidase is any enzyme that catalyzes an oxidation/reduction reaction involving molecular oxygen (O2) as the electron acceptor. ... Glutathione Peroxidase 1 A peroxidase (eg. ... In biochemistry, a transferase is an enzyme that catalyzes the transfer of a functional group (e. ... This list contains a list of EC numbers for the second group, EC 2, transferases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... Methyltransferase can refer to: DNA methyltransferase Histone methyltransferase Category: ... Acetyl Acyltransferase is a type of transferase enzyme which acts upon acyl groups. ... Glycosyltransferases are a group of enzymes that act as a catalyst for the transfer of a monosaccharide from a glycosylamine derivative to an acceptor. ... In biochemistry, a transaminase or an aminotransferase is an enzyme that catalyzes a type of reaction between an amino acid and an Î±-keto acid. ... Phosphotransferase is a category of enzymes with the quality of catalyzing phosphorylation. ... ITaq DNA polymerase A polymerase (EC 2. ... In biochemistry, a kinase is a type of enzyme that transfers phosphate groups from high-energy donor molecules, such as ATP, to specific target molecules (substrates); the process is termed phosphorylation. ... In biochemistry, a hydrolase is an enzyme that can break a chemical bond by hydrolysis. ... This list contains a list of EC numbers for the third group, EC 3, hydrolases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... An esterase is an hydrolase enzyme that splits esters into a acid and an alcohol in a chemical reaction with water called hydrolysis. ... DNA glycosylases are a family of enzymes involved in base excision repair. ... Glycoside hydrolases (also called glycosidases) catalyze the hydrolysis of the glycosidic linkage to generate two smaller sugars. ... Helicases are a class of enzymes vital to all living organisms. ... In biochemistry, a lyase is an enzyme that breaks various chemical bonds by means other than hydrolysis and oxidation, often forming a new double bond or a new ring structure. ... This list contains a list of EC numbers for the fourth group, EC 4, lyases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... Carboxy-lyases, also known as decarboxylases, are carbon-carbon lyases that add or remove a carboxyl group from organic compounds. ... Aldolase is an enzyme which catalyses the aldol reaction: The substrate, fructose 1,6-bisphosphate (F-1,6-BP) is broken down into glyceraldehyde 3-phosphate and dihydroxyacetone phosphate (DHAP). ... Dehydratase is an enzyme that catalyzes the removal of oxygen and hydrogen from organic compounds in the form of water. ... In biochemistry, a synthase is an enzyme which catalyzes a synthesis process. ... In biochemistry, an isomerase is any enzyme that catalyses the interconversion of isomers. ... This list contains a list of EC numbers for the fifth group, EC 5, isomerases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... An enzyme that catalyzes the shifting of a functional group from one position to another within the same molecule. ... Topoisomerases (type I: EC 5. ... In biochemistry, a ligase (from the Latin verb ligÄre â€” to bind or to glue together) is an enzyme that can catalyse the joining of two large molecules by forming a new chemical bond, usually with accompanying hydrolysis of a small chemical group pendant to one of the larger molecules. ... This list contains a list of EC numbers for the sixth group, EC 6, ligases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... It has been suggested that sticky end/blunt end be merged into this article or section. ... An aminoacyl tRNA synthetase (abbreviated aaRs) is an enzyme that catalyzes the binding of a specific amino acid to a tRNA to form an aminoacyl-tRNA. The synthetase hydrolyzes ATP to bind the appropriate amino acid to the 3 hydroxyl of the tRNA molecule. ...

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Hydrolase: proteases

Endopeptidase, Exopeptidase In biochemistry, a hydrolase is an enzyme that can break a chemical bond by hydrolysis. ... Peptidases (proteases [pronounced pro-tea-aces] and proteolytic enzymes are also commonly used) are enzymes which break peptide bonds of proteins. ... An exopeptidase is an enzyme that catalyses the removal of an amino acid from the end of a polypeptide chain. ...

Serine protease: Chymotrypsin, Trypsin, Elastase, Plasmin, Proteinase 3 Crystal structure of Trypsin, a typical serine protease. ... Chymotrypsin (bovine Î³ chymotrypsin: PDB 1AB9, EC 3. ... Trypsin (EC 3. ... Protein Crystal Growth Porcine Elastase In molecular biology, elastase is an enzyme from the class of proteases (or better peptidases) that break down proteins. ... Plasmin is an important degrading enzyme (EC 3. ... Proteinase 3 is a serine protease enzyme expressed mainly in neutrophil granulocytes. ...

Cysteine protease: Papain, Cathepsin, Caspase, Calpain Proteases are enzymes that degrade polypeptides. ... Papain is a protease enzyme (EC 3. ... A cathepsin is a type of protease, ie a type of protein that breaks apart other proteins. ... Caspases are a group of cysteine proteases, enzymes with a crucial cysteine residue that can cleave other proteins after an aspartic acid residue, a specificity which is unusual among proteases. ... Calpain is calcium-dependent, non-lysosomal proteolytic enzyme found in the brain (Castillo and Babson, 1998). ...

Metalloproteinase: Procollagen peptidase, Thermolysin, ADAM protein (ADAMTS2, ADAMTS13, ADAMTS5, ADAM17), Matrix metalloproteinase (Collagenase) The metalloendopeptidases (also called metalloproteinases or metalloproteases) are a class of enzymes from the group of endopeptidases. ... Procollagen peptidase is an endopeptidase involved in the processing of collagen. ... Thermolysin is an metalloproteinase enzyme classified under EC 3. ... Adam protein (A Disintegrin and Metalloproteinase Protein) is a type of peptidase protein. ... ADAMTS2 (ADAM metallopeptidase with thrombospondin type 1 motif, 2) is a gene that produces an enzyme that is responsible for processing several types of procollagen proteins. ... ADAMTS13 (A Disintegrin And Metalloproteinase with a ThromboSpondin type 1 motif, member 13) is a zinc-containing metalloprotease enzyme that cleaves von Willebrand factor (vWf), a large protein involved in blood clotting. ... ADAMTS5 is an enzyme that destroys cartilage in mice. ... Physical Characteristics The ADAM metallopeptidase domain 17(ADAM17) also called TACE is an enzyme that belongs to the ADAM Protein (A Disintegrin and Metalloprotease) family. ... Matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases; other family members are adamalysins, serralysins, and astacins. ... Collagenases are enzymes that break the peptide bonds in collagen. ...

Aspartic acid protease: Pepsin - Chymosin - Renin - Plasmepsin - Signal peptide peptidase Aspartic acid Aspartic acid proteases are protease enzymes which have an aspartic acid residue in the active site of the enzyme. ... Pepsin is a digestive protease (EC 3. ... Rennet, also called rennin or chymosin (EC 3. ... Renin, also known as angiotensinogenase, is a circulating enzyme (EC 3. ... Plasmepsins are a class of at least 10 enzymes produced by the plasmodium parasite. ... Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. ...

Contents

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