TABLE 1.

Comparison of kinetic parameters for KPC-1, KPC-2, and KPC-3a

SubstrateKm or Ki (μM)kcat (s−1)kcat/Km (μM−1 s−1)
KPC-1KPC-2KPC-3KPC-1KPC-2KPC-3KPC-1KPC-2KPC-3
Ampicillin13023965 (±5)11021077 (±4)0.90.91.2
NitrocefinNAbNA42 (±5)NANA107 (±5)NANA2.6
Cephaloridine560500261 (±1)340530364 (±4)0.61.11.4
Cephalotin538244 (±3)7569153 (±5)1.40.83.5
Cefotaxime16022095 (±8)142252 (±4)0.10.10.5
Ceftazidime94NA88 (±1)0.10.13 (±0.06)0.001NA0.03
Cefoxitinc120180970 (±65)0.30.30.05d (±0.001)0.0020.0020.5d
MoxalactamcNANA14 (±1.6)NANA0.008 (±0.0002)NANA0.05
Meropenem12154 (±1)346 (±0.09)0.30.31.4
Imipenem815123 (±6)121545 (±0.04)0.20.31.9
SulbactamNANA30 (±0.9)NANA4 (±0.1)NANA0.1
  • a Kinetic values used for KPC-1 and KPC-2 were reported by H. Yigit et al. (29, 30).

  • b NA, not available.

  • c Ki values were obtained using 100 μM nitrocefin as a reporter substrate.

  • d kcat values were obtained by hydrolyzing a low concentration of substrate with a high concentration of enzyme.