TABLE 5.

Main kinetic similarities and differences among the three variants of AmpC from M. morganii

AntibioticAmpC enzymekcat (s−1)Km (μM)kcat/Km (μM−1 · s−1)
AmpicillinM190.06 ± 0.0030.08 ± 0.0040.75 ± 0.04
M290.06 ± 0.0030.13 ± 0.0090.5 ± 0.02
M370.06 ± 0.0030.06 ± 0.0061 ± 0.05
ImipenemM190.11 ± 0.0064 ± 0.10.027 ± 0.002
M290.07 ± 0.0032 ± 0.30.035 ± 0.002
M370.07 ± 0.0041 ± 0.060.07 ± 0.004
CephalothinM1914 ± 246 ± 130.3 ± 0.04
M29140 ± 35148 ± 101 ± 0.2
M376 ± 0.8106 ± 100.06 ± 0.007
CefotaximeM19≤0.07 ± 0.0040.5 ± 0.060.14 ± 0.008
M290.032 ± 0.0020.02 ± 0.00161.6 ± 0.1
M37≤0.09 ± 0.0030.09 ± 0.011 ± 0.03