β-lactamases (EC 184.108.40.206) [1,2] are enzymes which catalyze the hydrolysis
of an amide bond in the β-lactam ring of antibiotics belonging to the
penicillin/cephalosporin family. Four kinds of β-lactamase have been
identified . Class-B enzymes are zinc containing proteins whilst class -A,
C and D enzymes are serine hydrolases. Class-B β-lactamases have been
described in several Gram-negative bacterial species; they seem to share the
characteristic of being able to hydrolyze carbapenem compounds which are new
β-lactam antibiotics of great therapeutic potential.
There are a number of conserved regions in the sequence of known class-B β-lactamases . Most of them are centered on residues known  to be involved
in binding the zinc ion essential for the enzyme's catalytic activity. We
designed two signature patterns for this class of enzyme. The first contains
three residues involved in binding zinc ions. The second pattern contains a
cysteine which is also a zinc ligand.
April 2003 / Patterns and text revised.
PROSITE methods (with tools and information) covered by this documentation:
The structure of beta-lactamases.
Philos. Trans. R. Soc. Lond., B, Biol. Sci. 289:321-331(1980).
PROSITE is copyright. It is produced by the SIB Swiss Institute
Bioinformatics. There are no restrictions on its use by non-profit
institutions as long as its content is in no way modified. Usage by and
for commercial entities requires a license agreement. For information
about the licensing scheme send an email to
or see: prosite_license.html.