Table 3.

Kinetic parameters for TEM-43 β-lactamase

Antibiotickcat(s−1)RelativekcatKm (μM)kcat/Km mM−1 s−1Relativekcat/Km
Benzylpenicillin240100269,200100
Ampicillin4920133,80041
Carbenicillin2611396707.3
Piperacillin190791201,60017
Oxacillin187.5218609.3
Cloxacillin6.42.7164004.3
Cephalothin2611554705.1
Cephaloridine170711201,40015
Nitrocefin12050442,70029
Cefuroxime7.53.1164705.1
Cefotaxime6.92.8332102.3
Ceftriaxone2.81.2102803.0
Ceftazidime43181602702.9
Cefoperazone3.01.37.63904.2
Cefoxitin0.02<0.001NDa NDND
Imipenem0.02<0.001ND NDND
Aztreonam4218577408.0
  • a ND, not determined. The hydrolysis rate was too slow to obtain an accurate Km .