Peptidase activity of β-lactamases

Noureddine Rhazi, Moreno Galleni, Michael I. Page, Jean Marie Frère

Research output: Contribution to journalArticlepeer-review

25 Citations (Scopus)


Although β-lactamases have generally been considered as being devoid of peptidase activity, a low but significant hydrolysis of various N-acylated dipeptides was observed with representatives of each class of β-lactamases. The k(cat)/K(m) values were below 0.1 M-1.s-1, but the enzyme rate enhancement factors were in the range 5000-20000 for the best substrates. Not unexpectedly, the best 'peptidase' was the class C β-lactamase of Enterobacter cloacae P99, but, more surprisingly, the activity was always higher with the phenylacetyl- and benzoyl-D-Ala-D-Ala dipeptides than with the diacetyl- and α-acetyl-L-Lys-D-Ala-D-Ala tripeptides, which are the preferred substrates of the low-molecular-mass, soluble DD-peptidases. A comparison between the β-lactamases and DD-peptidases showed that it might be as difficult for a DD-peptidase to open the β-lactam ring as it is for the β-lacetamases to hydrolyse the peptides, an observation which can be explained by geometric and stereoelectronic considerations.

Original languageEnglish
Pages (from-to)409-413
Number of pages5
JournalBiochemical Journal
Issue number2
Publication statusPublished - 15 Jul 1999


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