Trypsin

Lysosomal enzyme class enzyme that catalyzes the hydrolytic breakdown of proteins, peptides, amides, and esters via the peptide bond. Optimal activity in a weakly alkaline environment. Enters the duodenum from the pancreas as trypsinogen. It is activated by the enzyme synthesized in the upper part of the small intestine called enterokinase, which cleaves a acidic hexapeptide from the N-terminus of trypsinogen. Enterokinase is a specific activator of trypsinogen. It cleaves the peptide bond composed of the carboxyl group of lysine and the amino group of isoleucine. Thus, trypsin hydrolyzes peptide bonds involving the carboxyl groups of basic amino acids (lysine and arginine). The secretion of enterokinase is stimulated by trypsin, chymotrypsin, bile acids, and cholecystokinin. Upon cleaving the hexapeptide, the active center of trypsin is formed, which contains the amino acid serine. The activity of enterokinase requires Ca ions. The pancreas produces trypsin inhibitor (antitrypsin) to protect it from self-digestion. Trypsin itself is an activator of other proteases.

Source | Glossary of Most Commonly Used Biomedical Terms and Concepts | Lithuanian University of Health Sciences | Academician Professor Antanas Praškevičius, Professor Laima Ivanovienė