Kinetics study of KPC-3, a plasmid-encoded class a carbapenem-hydrolyzing β-lactamase

The kinetic activity of KPC-3, a plasmid-encoded class A carbapenemase, was studied. It hydrolyzed penicillins, cephalosporins, carbapenems, and even sulbactam. The best substrate was cephalothin (k(cat)/(K)m = 3.48 mu M-1 s(-1)). The efficiency of the enzyme was similar for imipenem and meropenem (k(cat)/K-m, 1.4 and 1.94 mu M-1 s(-1), respectively).