S1A family serine protease

S1A family serine protease refers to a large and well-studied group of enzymes primarily defined by a common structural fold (chymotrypsin/trypsin-like, Clan PA, Subclan S1A) and the presence of a catalytic triad (His, Asp, Ser) at the active site[5][2][1]. These enzymes are widespread in animals and include trypsins, chymotrypsins, elastases, granzymes, thrombin, and kallikreins. They predominantly act extracellularly to cleave peptide bonds following positively charged or bulky hydrophobic residues, depending on substrate specificity[2][3][1]. S1A proteases are essential for digestion, blood coagulation, immune defense, apoptotic cell death, and regulation of inflammation. Dysfunction or dysregulation contributes to cancer, cardiovascular disease, and inflammatory and neurodegenerative disorders[2][3][5]. Because of their pivotal biological roles, they are major therapeutic targets, especially in the context of blood clotting, inflammation, and immune modulation, but require careful inhibition due to their central role in vital physiological processes[1][2][5][6].

Other names

chymotrypsin family serine proteasetrypsin-like serine proteasechymotrypsin/trypsin familypeptidase S1A

Competitive inhibition at active site (e.g., serine residue binding); Selective covalent or noncovalent blockade of the catalytic triad; Allosteric inhibition; Zymogen inactivation/prevention of activation; Peptide bond cleavage inhibition