Serine protease trypsin (trypsin)

Serine protease trypsin is a medium-sized globular enzyme primarily produced in the pancreas as the inactive precursor trypsinogen, which is activated in the small intestine[1][5][7]. It cleaves peptide bonds at the carboxyl side of lysine and arginine residues in proteins[1][2], making it crucial for protein digestion[5]. Trypsin possesses a classic catalytic triad (Ser-195, His-57, Asp-102) at its active site, which enables nucleophilic attack on peptide substrates[1][3]. It operates in an allosterically regulated fashion and features additional regulatory sites (e.g., calcium binding loop) that modulate its activity[1][4]. Excessive or inappropriate activation can contribute to pancreatitis, while its essential role in digestion means trypsin deficiency can lead to malabsorption[5]. Trypsin inhibitors, both natural (such as BPTI and pancreatic trypsin inhibitor) and synthetic (serine protease inhibitor drugs), are therapeutically relevant for managing hyperactive trypsin activity and related disease states[5]. Trypsin is also used as a biomarker in diagnostic assays, and its mechanism has served as a model for understanding serine protease family functions in physiology and disease[1][2][7][8].

Other names

TrypsinSerine protease 1Serine endopeptidase trypsinTrypsin-1

Competitive inhibition of active site serine; Irreversible covalent modification of the catalytic triad; Allosteric inhibition at regulatory loops