|Trypsin is a proteolytic enzyme that hydrolyzes peptide bonds on the carboxyl side of the amino acids arginine and lysine. Trypsin is a serine endopeptidase that catalyzes the cleavage of peptide bonds on the carboxyl side of either arginine or lysine. Trypsin is one
of the three principal digestive proteinases, the other two being pepsin and chymotrypsin. Trypsin is produced in the pancreas in
the form of trypsinogen, and is then transported to the small intestine, where begins the digestion of proteins to polypeptides and amino acids. As pepsin, trypsin digests proteins into peptides and amino acids and is made and secreted in an inactive form, trypsinogen. Trypsinogen is the inactive precursor of trypsin, which is secreted by the exocrine cells of the pancreas and then released into the lumen of the small intestine. Trypsinogen is converted to the active trypsin by enterokinase from the intestinal mucosa and by trypsin itself. Trypsin is present in the digestive tract of a wide variety of mammals. Trypsin is typically prepared from the duodenal glands of various animal species and purified to different grades of purity.
Trypsin catalyzes the cleavage and activation of additional trypsinogen and other pancreatic proenzymes important to protein digestion. In the digestive process, trypsin acts with the other proteinases to break down dietary protein molecules to their component peptides and amino acids. Trypsin continues the process of digestion (begun in the stomach) in the small intestine where a slightly alkaline environment (about pH 8) promotes its maximal enzymatic activity. Trypsin hydrolyzes peptide bonds in which the carbonyl group is contributed by the basic amino acids lysine or arginine. Trypsin cuts proteins only at carboxyl side of lysine and arginine residues (endopeptidase) by hydrolysis. A small amount of another enzyme, enterokinase, is required to catalyze the initial reaction of trypsinogen to trypsin. Trypsin stimulates glucose uptake and activate pyruvate dehydrogenase and glycogen synthase. It also stimulates autophosphorylation of insulin receptors and also insulin receptor-associated tyrosine kinase activity. With these actions, trypsin can be labeled an insulin mimetic enzyme. In summary, its function is the hydrolytic cleavage of peptide bonds, thus reducing the size of large proteins and making them accessible to further degradation by other proteases.
Trypsin has a wide range of industrial and scientific uses. Trypsin is used in biotechnological applications, especially in the cultivation of mammalian cells. Trypsin is also used as a protein degrading enzyme in the processing of non-trypsin sensitive biopolymers. Trypsin can be inactivated or inhibited by a number of specific or non-specific protease inhibitors, many of them belonging to the serpine family. The most widely used in biotechnological applications is a trypsin inhibitor from soy beans. Trypsin is commonly used in formalin-fixed, paraffin-embedded immunohistochemical procedures. In humans, trypsin is associated with many disorders. Imbalances in regulation of trypsin cause imbalances in insulin. Imbalances in other regions of the body of trypsin and trypsin-like proteins are thought to play a role in many other disorders such as emphysema, asthma, arthritis, skin disorders, and cancerous tumor growth.