Trypsin and related serine proteases

Trypsin and related serine proteases constitute a large family of enzymes, primarily the S1 peptidase family, characterized by a conserved catalytic triad of serine, histidine, and aspartate (UniProt, P07477). These enzymes are essential for diverse physiological processes, including the digestion of dietary proteins in the small intestine and the regulation of complex proteolytic cascades such as blood coagulation and fibrinolysis (StatPearls, NBK537005). Beyond digestion and hemostasis, they participate in immune responses through the complement system and cellular signaling via the activation of protease-activated receptors (PubMed, 21439468). Dysregulation of these proteases is implicated in numerous diseases; for instance, premature activation of trypsin within the pancreas leads to pancreatitis, while aberrant activity of coagulation factors causes thrombosis (Wikipedia, Serine protease). Furthermore, certain serine proteases like TMPRSS2 are exploited by viruses, including SARS-CoV-2, to facilitate cellular entry (DrugBank, DB09224). Therapeutic intervention often involves the use of small-molecule inhibitors like camostat or nafamostat to treat inflammatory and infectious conditions, or specific anticoagulants like rivaroxaban that target individual factors in the coagulation cascade (DrugBank, DB06695). However, the high structural similarity among family members poses a significant challenge for drug design, as off-target inhibition can lead to adverse effects such as bleeding or impaired digestion.

Other names

S1 family peptidasesTrypsin-like serine proteasesSerine endopeptidasesChymotrypsin-like proteases

Competitive inhibition of the catalytic active site; covalent or non-covalent binding to the serine residue in the catalytic triad; inhibition of protease-activated receptor (PAR) signaling.