Acting on peptide bonds (peptidases);
Exhibits low specificity towards esters of amino acids with small hydrophobic or aromatic residues at the P1 position
This enzyme from the extreme thermophile, Thermus aquaticus, is an alkaline serine peptidase. It has three subsites, S1, S2, and S3, in the substrate binding site. The preferred amino acids at the S1 site are Ala and Phe, at the S2 site are Ala and norleucine and at the S3 site are Phe and Ile . These specificities are similar to those of EC 22.214.171.124 (peptidase K) and EC 126.96.36.199 (subtilisin BPN') . The enzyme displays broad specificity for cleavage of insulin B-chain and hydrolyses elastin substrates such as succinyl-(Ala)n-p-nitroanilide (n = 1,2,3) and some peptide esters [1,3]. Belongs in peptidase family S8A.