EC 3.5.2.6     
Accepted name: β-lactamase
Reaction: a β-lactam + H2O = a substituted β-amino acid
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; carbapenemase
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 3.5.2.8, cephalosporinase.
References:
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. (Ed.), 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. [PMID: 13303985]
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 3.5.2.6 created 1961, modified 1981 (EC 3.5.2.8 created 1972, incorporated 1978)]