Hydrolases;
Acting on peptide bonds (peptidases);
Serine endopeptidases
Reaction(IUBMB)
Exhibits low specificity towards esters of amino acids with small hydrophobic or aromatic residues at the P1 position
Comment
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 [3]. These specificities are similar to those of EC 3.4.21.64 (peptidase K) and EC 3.4.21.62 (subtilisin BPN') [3]. 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.
Tanaka T, Matsuzawa H, Kojima S, Kumagai I, Miura K, Ohta T.
Title
P1 specificity of aqualysin I (a subtilisin-type serine protease) from Thermus aquaticus YT-1, using P1-substituted derivatives of Streptomyces subtilisin inhibitor.
Substrate Specificity of Aqualysin I, a Bacterial Thermophilic Alkaline Serine Protease from Thermus aquaticus YT-1: Comparison with Proteinase K, Subtilisin BPN' and Subtilisin Carlsberg.
