ExplorEnz: EC 3.4.22.40

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3.4.22.40

Accepted name:

bleomycin hydrolase

Reaction:

Inactivates bleomycin B2 (a cytotoxic glycometallopeptide) by hydrolysis of a carboxyamide bond of β-aminoalanine, but also shows general aminopeptidase activity. The specificity varies somewhat with source, but amino acid arylamides of Met, Leu and Ala are preferred [1]

Other name(s):

aminopeptidase C (Lactococcus lactis) [4]

Comments:

The molecule is a homohexamer in which the monomers have a papain-like tertiary structure (in peptidase family C1). The active sites are on the walls of a central channel through the molecule, and access of substrate molecules to them is obstructed by this and by the C-terminus of each polypeptide chain [3]. Bleomycin can scarcely be the natural substrate, and there are reports of limited endopeptidase activity. Known from bacteria as well as eukaryotic organisms. Hydrolase H from chicken muscle has many similarities to bleomycin hydrolase, but hydrolyses Ph-CO-Arg-2-naphthylamine as well as aminopeptidase substrates [2].

Links to other databases:

BRENDA, EXPASY, KEGG, MetaCyc, MEROPS, PDB, CAS registry number: 53096-17-6

References:

1.	Brömme, D., Rossi, A.B., Smeekens, S.P., Anderson, D.C. & Payan, D.G. Human bleomycin hydrolase: molecular cloning, sequencing, functional expression, and enzymatic characterization. Biochemistry 35 (1996) 6706–6714. [DOI] [PMID: 8639621]
2.	Adachi, H., Tsujimoto, M., Fukasawa, M., Sato, Y., Arai, H., Inoue, K. and Nishimura, T. cDNA cloning and expression of chicken aminopeptidase H, possessing endopeptidase as well as aminopeptidase activity. Eur. J. Biochem. 245 (1997) 283–288. [DOI] [PMID: 9151954]
3.	Zheng, W., Johnston, S.A. & Joshua-Tor, L. The unusual active site of Gal₆/bleomycin hydrolase can act as a carboxypeptidase, aminopeptidase, and peptide ligase. Cell 93 (1998) 103–109. [DOI] [PMID: 9546396]
4.	Mistou, M.Y. & Gripon, J.C. Catalytic properties of the cysteine aminopeptidase PepC, a bacterial bleomycin hydrolase. Biochim. Biophys. Acta 1383 (1998) 63–70. [DOI] [PMID: 9546047]

[EC 3.4.22.40 created 2000]