IUBMB Enzyme Nomenclature


Accepted name: β-lactamase

Reaction: A β-lactam + H2O = a substituted β-amino acid

For diagram click here.

Other name(s): penicillinase; cephalosporinase; neutrapen; penicillin β-lactamase; exopenicillinase; ampicillinase; penicillin amido-β-lactamhydrolase; penicillinase I; penicillinase II; β-lactamase I; β-lactamase II; β-lactamase III; β-lactamase A; β-lactamase B; β-lactamase C; β-lactamase AME I; cephalosporin-β-lactamase

Systematic name: β-lactam hydrolase

Comments: A group of enzymes of varying specificity hydrolysing β-lactams; some act more rapidly on penicillins, some more rapidly on cephalosporins. The latter were formerly listed as EC, cephalosporinase.

Links to other databases: BRENDA, EXPASY, GTD, KEGG, Metacyc, PDB, CAS registry number: 9073-60-3


1. Citri, N. Penicillinase and other β-lactamases, in Boyer, P.D. (Ed.), The Enzymes, 3rd edn., vol. 4, Academic Press, New York, 1971, pp. 23-46.

2. Hennessey, T.D. and Richmond, M.H. The purification and some properties of a β-lactamase (cephalosporinase) synthesized by Enterobacter cloacae. Biochem. J. 109 (1968) 469-473. [PMID: 5685878]

3. Kuwabara, S. Purification and properties of two extracellular β-lactamases from Bacillus cereus 569-H. Biochem. J. 118 (1970) 457-465. [PMID: 4990588]

4. Pollock, M.R. Penicillinase, in Boyer, P.D., Lardy, H. and Myrbäck, K. (Eds.), The Enzymes, 2nd edn., vol. 4, Academic Press, New York, 1960, pp. 269-278.

5. Pollock, M.R., Torriani, A.-M. and Tridgell, E.G. Crystalline bacterial penicillinase. Biochem. J. 62 (1956) 387-391.

6. Ross, G.W. and Boulton, M.G. Purification of β-lactamases on QAE-sephadex. Biochim. Biophys. Acta 309 (1973) 430-439. [PMID: 4731970]

[EC created 1961, modified 1981 (EC created 1972, incorporated 1978)]

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