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. Trypsin was discovered in 1876 by Wilhelm Kühne and was named from the Ancient Greek word for rubbing since it was first isolated by rubbing the pancreas with glycerin.
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.
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.
Cathepsins are proteases found in all animals as well as other organisms. There are approximately a dozen members of this family, which are distinguished by their structure, catalytic mechanism, and which proteins they cleave. Most of the members become activated at the low pH found in lysosomes. Thus, the activity of this family lies almost entirely within those organelles. There are, however, exceptions such as cathepsin K, which works extracellularly after secretion by osteoclasts in bone resorption. Cathepsins have a vital role in mammalian cellular turnover.
Enteropeptidase is an enzyme produced by cells of the duodenum and is involved in digestion in humans and other animals. Enteropeptidase converts trypsinogen into its active form trypsin, resulting in the subsequent activation of pancreatic digestive enzymes. Absence of enteropeptidase results in intestinal digestion impairment.
Kallikreins are a subgroup of serine proteases, enzymes capable of cleaving peptide bonds in proteins. In humans, plasma kallikrein has no known paralogue, while tissue kallikrein-related peptidases (KLKs) encode a family of fifteen closely related serine proteases. These genes are localised to chromosome 19q13, forming the largest contiguous cluster of proteases within the human genome. Kallikreins are responsible for the coordination of various physiological functions including blood pressure, semen liquefaction and skin desquamation.
Cathepsin C (CTSC) also known as dipeptidyl peptidase I (DPP-I) is a lysosomal exo-cysteine protease belonging to the peptidase C1 protein family, a subgroup of the cysteine cathepsins. In humans, it is encoded by the CTSC gene.
Collagenases are enzymes that break the peptide bonds in collagen. They assist in destroying extracellular structures in the pathogenesis of bacteria such as Clostridium. They are considered a virulence factor, facilitating the spread of gas gangrene. They normally target the connective tissue in muscle cells and other body organs.
In molecular biology, the Signal Peptide Peptidase (SPP) is a type of protein that specifically cleaves parts of other proteins. It is an intramembrane aspartyl protease with the conserved active site motifs 'YD' and 'GxGD' in adjacent transmembrane domains (TMDs). Its sequences is highly conserved in different vertebrate species. SPP cleaves remnant signal peptides left behind in membrane by the action of signal peptidase and also plays key roles in immune surveillance and the maturation of certain viral proteins.
Alpha 1-antichymotrypsin is an alpha globulin glycoprotein that is a member of the serpin superfamily. In humans, it is encoded by the SERPINA3 gene.
Thermolysin is a thermostable neutral metalloproteinase enzyme produced by the Gram-positive bacteria Bacillus thermoproteolyticus. It requires one zinc ion for enzyme activity and four calcium ions for structural stability. Thermolysin specifically catalyzes the hydrolysis of peptide bonds containing hydrophobic amino acids. However thermolysin is also widely used for peptide bond formation through the reverse reaction of hydrolysis. Thermolysin is the most stable member of a family of metalloproteinases produced by various Bacillus species. These enzymes are also termed 'neutral' proteinases or thermolysin -like proteinases (TLPs).
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.
Tripeptidyl-peptidase 1, also known as Lysosomal pepstatin-insensitive protease, is an enzyme that in humans is encoded by the TPP1 gene. TPP1 should not be confused with the TPP1 shelterin protein which protects telomeres and is encoded by the ACD gene. Mutations in the TPP1 gene leads to late infantile neuronal ceroid lipofuscinosis.
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.
Nepenthesin is an aspartic protease of plant origin that has so far been identified in the pitcher secretions of Nepenthes and in the leaves of Drosera peltata. It is similar to pepsin, but differs in that it also cleaves on either side of Asp residues and at Lys┼Arg. While more pH and temperature stable than porcine pepsin A, it is considerably less stable in urea or guanidine hydrochloride. It is the only known protein with such a stability profile.
Gemigliptin (rINN), sold under the brand name Zemiglo, is an oral anti-hyperglycemic agent of the dipeptidyl peptidase-4 inhibitor class of drugs. Glucose lowering effects of DPP-4 inhibitors are mainly mediated by GLP-1 and gastric inhibitory polypeptide (GIP) incretin hormones which are inactivated by DPP-4.
Peptidase 1 (mite) (EC 3.4.22.65), also known as endopeptidase 1 (mite), is an enzyme found in various species of mites. This enzyme exhibits cysteine protease activity with broad endopeptidase specificity.
Pycnoporopepsin is an enzyme. This enzyme catalyses the following chemical reaction
Serralysin is an enzyme. This enzyme catalyses the following chemical reaction
The sedolisin family of peptidases are a family of serine proteases structurally related to the subtilisin (S8) family. Well-known members of this family include sedolisin ("pseudomonalisin") found in Pseudomonas bacteria, xanthomonalisin ("sedolisin-B"), physarolisin as well as animal tripeptidyl peptidase I. It is also known as sedolysin or serine-carboxyl peptidase. This group of enzymes contains a variation on the catalytic triad: unlike S8 which uses Ser-His-Asp, this group runs on Ser-Glu-Asp, with an additional acidic residue Asp in the oxyanion hole.
