TABLE 3.

Kinetic parameters of the wild-type and N233A CphA enzymesa

β-Lactam antibioticWTN233A
kcat (s−1)Km (μM)kcat/Km (M−1 s−1)kcat (s−1)Km (μM)kcat/Km (M−1 s−1)
Imipenem1,2003403,500,000>700>1,000700,000
Nitrocefin0.0081,30060.0355520
CENTANHNHNH0.003514250
  • a All the experiments were performed at 30°C in 15 mM cacodylate (pH 6.5) with <0.4 μM Zn2+. Standard errors were below 10%. NH, no observed hydrolysis; WT, wild type.