Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids. Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called proteases, but may also occur by intra-molecular digestion.
Trypsin is an enzyme in the first section of the small intestine that starts the digestion of protein molecules by cutting long chains of amino acids into smaller pieces. It is a serine protease from the PA clan superfamily, found in the digestive system of many vertebrates, where it hydrolyzes proteins. Trypsin is formed in the small intestine when its proenzyme form, the trypsinogen produced by the pancreas, is activated. Trypsin cuts peptide chains mainly at the carboxyl side of the amino acids lysine or arginine. It is used for numerous biotechnological processes. The process is commonly referred to as trypsinogen proteolysis or trypsinization, and proteins that have been digested/treated with trypsin are said to have been trypsinized.
The pineapple is a tropical plant with an edible fruit; it is the most economically significant plant in the family Bromeliaceae.
A protease is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds. Proteases are involved in numerous biological pathways, including digestion of ingested proteins, protein catabolism, and cell signaling.
The enzyme fructose bisphosphatase (EC 3.1.3.11; systematic name D-fructose-1,6-bisphosphate 1-phosphohydrolase) catalyses the conversion of fructose-1,6-bisphosphate to fructose 6-phosphate in gluconeogenesis and the Calvin cycle, which are both anabolic pathways:
Bradykinin (BK) (from Greek brady- 'slow' + -kinin, kīn(eîn) 'to move') is a peptide that promotes inflammation. It causes arterioles to dilate (enlarge) via the release of prostacyclin, nitric oxide, and endothelium-derived hyperpolarizing factor and makes veins constrict, via prostaglandin F2, thereby leading to leakage into capillary beds, due to the increased pressure in the capillaries. Bradykinin consists of nine amino acids, and is a physiologically and pharmacologically active peptide of the kinin group of proteins.
Bromelain is an enzyme extract derived from the stems of pineapples, although it exists in all parts of the fresh plant and fruit. The extract has a history of folk medicine use. As a culinary ingredient, it may be used as a meat tenderizer.
Transglutaminases are enzymes that in nature primarily catalyze the formation of an isopeptide bond between γ-carboxamide groups ( -(C=O)NH2 ) of glutamine residue side chains and the ε-amino groups ( -NH2 ) of lysine residue side chains with subsequent release of ammonia ( NH3 ). Lysine and glutamine residues must be bound to a peptide or a protein so that this cross-linking (between separate molecules) or intramolecular (within the same molecule) reaction can happen. Bonds formed by transglutaminase exhibit high resistance to proteolytic degradation (proteolysis). The reaction is
Papain, also known as papaya proteinase I, is a cysteine protease enzyme present in papaya and mountain papaya. It is the namesake member of the papain-like protease family.
An enzyme inhibitor is a molecule that binds to an enzyme and blocks its activity. Enzymes are proteins that speed up chemical reactions necessary for life, in which substrate molecules are converted into products. An enzyme facilitates a specific chemical reaction by binding the substrate to its active site, a specialized area on the enzyme that accelerates the most difficult step of the reaction.
Fruit bromelain is an enzyme. This enzyme catalyses the following chemical reaction
Ficain also known as ficin, debricin, or higueroxyl delabarre is a proteolytic enzyme extracted from the latex sap from the stems, leaves, and unripe fruit of the American wild fig tree Ficus insipida.
Actinidain is a type of cysteine protease enzyme found in fruits including kiwifruit, pineapple, mango, banana, figs, and papaya. This enzyme is part of the peptidase C1 family of papain-like proteases.
Caspase 4 is an enzyme that proteolytically cleaves other proteins at an aspartic acid residue (LEVD-), and belongs to a family of cysteine proteases called caspases. The function of caspase 4 is not fully known, but it is believed to be an inflammatory caspase, along with caspase 1, caspase 5, with a role in the immune system.
Proteases are in use, or have been proposed or tried, for a number of purposes related to medicine or surgery. Some preparations involving protease have undergone successful clinical trials and have regulatory authorization; and some further ones have shown apparently useful effects in experimental medical studies. Proteases have also been used by proponents of alternative therapies, or identified in materials of traditional or folk medicine. A serine protease of human origin, activated protein C, was produced in recombinant form and marketed as Drotrecogin alfa and licensed for intensive-care treatment of severe sepsis. It was voluntarily withdrawn by the manufacturer in 2011 after being shown to be ineffective.
Many major physiological processes depend on regulation of proteolytic enzyme activity and there can be dramatic consequences when equilibrium between an enzyme and its substrates is disturbed. In this prospective, the discovery of small-molecule ligands, like protease inhibitors, that can modulate catalytic activities has an enormous therapeutic effect. Hence, inhibition of the HIV protease is one of the most important approaches for the therapeutic intervention in HIV infection and their development is regarded as major success of structure-based drug design. They are highly effective against HIV and have, since the 1990s, been a key component of anti-retroviral therapies for HIV/AIDS.
Ebrotidine is an H2 receptor antagonist with gastroprotective activity against ethanol-, aspirin- or stress-induced gastric mucosal damage. The antisecretory properties of ebrotidine are similar to those of ranitidine, and approximately 10-fold greater than those of cimetidine. Ebrotidine has anti-Helicobacter pylori activity via inhibition of the urease enzyme and the proteolytic and mucolytic activities of the bacterium. However, its activity is synergistic with a number of antibacterial agents. Ebrotidine counteracts the inhibitory effects of H. pylori lipopolysaccharides. Ebrotidine was withdrawn from the market due to risks of hepatotoxicity.
Venombin A is an enzyme. This enzyme catalyses the following chemical reaction
Zingibain, zingipain, or ginger protease is a cysteine protease enzyme found in ginger rhizomes. It catalyses the preferential cleavage of peptides with a proline residue at the P2 position. It has two distinct forms, ginger protease I (GP-I) and ginger protease II (GP-II).
Bromelain, a concentrate of proteolytic enzymes from the pineapple plant, is used in medicine. It is approved in the European Union for the debridement of severe burn wounds under the brand name Nexobrid. It was developed by MediWound.
