Synonym(s): Penicillinase, Cephalosporinase <p>Beta-lactamases (<db_xref db="EC" dbkey="3.5.2.6"/>) are enzymes which catalyse the hydrolysis of an amide bond in the beta-lactam ring of antibiotics belonging to the penicillin/cephalosporin family. The class B enzymes are zinccontaining proteins whilst class A, C and D enzymes are serine hydrolases.Class B beta-lactamases have been described in several Gram-negativebacterial species; they seem to share the characteristic of being able tohydrolyse carbapenem compounds, new beta-lactam antibiotics of greattherapeutic potential.</p><p>The conserved regions in the sequence of known class B beta-lactamases arecentred on residues known to be involved in binding the zinc ion essentialfor the enzymes catalytic activity [<cite idref="PUB00000136"/>, <cite idref="PUB00005282"/>].</p> Beta-lactamase, class-B, conserved site