IUBMB Enzyme Nomenclature


Accepted name: aqualysin 1

Reaction: Exhibits low specificity towards esters of amino acids with small hydrophobic or aromatic residues at the P1 position

Other name(s): caldolysin

Comments: 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 (peptidase K) and EC (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.

Links to other databases: BRENDA, EXPASY, KEGG, MEROPS, Metacyc, PDB, CAS registry number: 88747-68-6


1. Matsuzawa, H., Tokugawa, K., Hamaoki, M., Mizoguchi, M., Taguchi, H., Terada, I., Kwon, S.T. and Ohta, T. Purification and characterization of aqualysin I (a thermophilic alkaline serine protease) produced by Thermus aquaticus YT-1. Eur. J. Biochem. 171 (1988) 441-447. [PMID: 3162211]

2. Tanaka, T., Matsuzawa, H., Kojima, S., Kumagai, I., Miura, K. and Ohta, T. P1 specificity of aqualysin I (a subtilisin-type serine protease) from Thermus aquaticus YT-1, using P1-substituted derivatives of Streptomyces subtilisin inhibitor. Biosci. Biotechnol. Biochem. 62 (1998) 2035-2038. [PMID: 9882104]

3. Tanaka, T., Matsuzawa, H. and Ohta, T. 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. Biosci. Biotechnol. Biochem. 62 (1998) 2161-2165.

[EC created 2006]

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