TABLE 2.

Kinetic parameters for hydrolysis of various β-lactam antibiotics by IMP-10 and IMP-1 metallo-β-lactamases

AntibioticKinetic parameter for β-lactamase (source)
IMP-10 (pMS601)IMP-1 (pMS501)
kcat (s−1)Km (μM)kcat/Km (μM−1 s−1)kcat (s−1)Km (μM)kcat/Km (μM−1 s−1)
Cephaloridine140 ± 1828 ± 0.85.062 ± 3.07 ± 0.48.9
Cephalothin230 ± 74.9 ± 0.34765 ± 2.92 ± 0.132.5
Cefotaxime74 ± 65.7 ± 0.31323 ± 1.91.4 ± 0.116
Ceftazidime51 ± 451 ± 4.51.016 ± 0.946 ± 10.3
BenzylpenicillinNDaND0.07460 ± 17240 ± 101.9
AmpicillinNDND0.06160 ± 15140 ± 91.1
CarbenicillinNDND0.1815 ± 2390 ± 120.04
PiperacillimNDND0.04200 ± 9280 ± 100.7
Imipenem220 ± 1160 ± 33.7130 ± 1130 ± 3.94.3
Meropenem64 ± 247 ± 1.51.413 ± 0.57 ± 1.21.9
  • a ND, not determined.