TABLE 2.

Kinetic properties of the purified IND-6 MBL with various β-lactam compoundsa

Substratekcat (s−1) for IND-6Km (μM) for IND-6kcat/Km value (M−1 s−1) for:
IND-6IND-2IND-5BlaB1
Benzylpenicillin305201.5 × 1074.6 × 1068.4 × 1052.7 × 107
Amoxicillin480855.6 × 106b
Carbenicillin210307.0 × 1065.3 × 1046.1 × 106
Cephalothin415606.9 × 1061.2 × 1061.6 × 106
Cephaloridine490905.4 × 1061.4 × 105
Cephalexin1936.3 × 106
Cefuroxime75233.3 × 1061.0 × 106
Cefotaxime8332.4 × 1059.0 × 1053.1 × 1047.9 × 105
Ceftazidime6222.7 × 1054.5 × 103NDd,e6.6 × 103
Cefepime>1.2>3004.0 × 1034.5 × 102NDd,e2.0 × 102
Nitrocefin115432.7 × 1063.9 × 106
Imipenem50133.8 × 1065.9 × 1052.4 × 1042.0 × 106
Meropenem251451.7 × 1051.8 × 1051.5 × 1047.6 × 105
AztreonamNHcNDdNDdNDdNDdNDd
  • a Standard deviations were below 10%. kcat/Km values for IND-2, IND-5, and BlaB1 are shown for comparison (8, 22, 26).

  • b −, data not available.

  • c NH, no hydrolysis detected with enzyme concentrations up to 0.9 μM.

  • d ND, not determined.

  • e Ceftazidime and cefepime are not hydrolyzed by IND-5 (22).