Assays for beta-lactamase activity and inhibition.

The ability, either innate or acquired, to produce beta-lactamases, enzymes capable of hydrolyzing the endocyclic peptide bond in beta-lactam antibiotics, would appear to be a primary contributor to the ever-increasing incidences of resistance to this class of antibiotics. To date, four distinct classes, A, B, C, and D, of beta-lactamases have been identified. Of these, enzymes in classes A, C, and D utilize a serine residue as a nucleophile in their catalytic mechanism while class B members are Zn2+-dependent for their function. Efforts have been and still continue to be made toward the development of potent inhibitors of these enzymes as a means to ensure the efficacy of beta-lactam antibiotics in clinical medicine. This chapter concerns procedures for the evaluation of the catalytic activity of beta-lactamases as a means to screen compounds for their inhibitory potency.