TABLE 4.

Steady-state kinetic parameters for the hydrolysis of β-lactam substrates of VIM-2 and its W87F and W87A mutantsa

Substratekcat (s−1)Km (μM)kcat/Km (μM−1 s−1)
VIM-2W87FW87AVIM-2W87FW87AVIM-2W87FW87A
Ampicillin12511516590561891.42.00.87
Cephalothin130130320111028121311
Cefuroxime812152018230.40.670.65
Cefotaxime70143251219835.87.50.3
Ceftazidime3.67.8≥0.15272170≥3500.050.0460.00043
Cefepime>40>20>4.5>400>450>3500.10.0480.012
Imipenem342211996223.83.75.4
Meropenem54535210182.54.51.9
  • a Standard deviations were below 10%.