Trypsin-3 (PRSS3)

Trypsin-3, also known as mesotrypsin and encoded by the PRSS3 gene, is one of three major human trypsin isoforms produced by the pancreas[5]. It is a serine protease enzyme responsible for the proteolytic cleavage of peptide bonds following lysine or arginine residues, primarily facilitating dietary protein digestion in the small intestine[8][5]. Unlike the more abundant trypsin-1 and trypsin-2, Trypsin-3 is notable for its resistance to common polypeptide trypsin inhibitors due to a unique structural modification (an arginine residue near its specificity pocket), allowing it to play a specialized role in degrading dietary and endogenous trypsin inhibitors that would otherwise impede protein digestion[5]. It is synthesized as an inactive zymogen (trypsinogen-3), secreted into the duodenum, and activated by enterokinase. Beyond its digestive function, Trypsin-3 can activate other digestive zymogens, participate in modulating inflammatory processes (notably via protease-activated receptors, especially PAR2), and has roles in metabolic regulation and disease pathogenesis, including possible involvement in pancreatic pathology, inflammation, and neurodegenerative diseases[4][5][8].

Other names

MesotrypsinPRSS3Serine protease 3Protease, serine 3

Proteolytic cleavage of peptide bonds after lysine or arginine - Inhibition by direct binding to active site (for inhibitors) - Drug inhibition by covalent or non-covalent binding to catalytic residues or substrate pocket