TABLE 3.

Kinetic parameters of AmpC M29 from Morganella morganii strain PP29 with different substrates

SubstrateKm (μM)kcat (s−1)kcat/Km (μM−1 · s−1)
Benzylpenicillina0.25 ± 0.0070.0074 ± 0.00040.03 ± 0.002
Ampicillina0.13 ± 0.0090.065 ± 0.0030.5 ± 0.02
Piperacillina0.17 ± 0.0051.5 ± 0.089 ± 0.4
Oxacillina0.003 ± 0.00030.022 ± 0.0017 ± 0.3
Imipenema2 ± 0.30.07 ± 0.0030.035 ± 0.002
Nitrocefin25 ± 493 ± 83.8 ± 0.3
Cephalothin148 ± 10140 ± 351 ± 0.2
Cefoxitina0.018 ± 0.00150.038 ± 0.00182.1 ± 0.1
Cefotaximea0.02 ± 0.00160.032 ± 0.0021.6 ± 0.1
Ceftazidimea0.9 ± 0.040.04 ± 0.0020.045 ± 0.002
Cefepimea95 ± 90.008 ± 0.00078 × 10−5 ± 7 × 10−6
  • a For these substrates, the Km value was determined as a Ki value using nitrocefin as a reporter substrate.