TABLE 3.
Kinetic parameters of β-lactam antibiotics for the purified carbapenem-hydrolyzing β-lactamase GOB-1
| Substrate | Km (μM) | kcat (s−1) | kcat/Km (μM−1·s−1)a |
|---|---|---|---|
| Benzylpenicillin | 109 | 204 | 1.87 |
| Amoxicillin | 1,024 | 357 | 0.35 |
| Ticarcillin | 147 | 76.3 | 0.52 |
| Piperacillin | 169 | 279 | 1.66 |
| Cephalothin | 24 | 16.1 | 0.67 |
| Cefepime | 52.6 | 10.7 | 0.20 |
| Cefoxitin | 46.8 | 11.9 | 0.25 |
| Cefuroxime | 26.9 | 26.3 | 0.98 |
| Ceftazidime | 71.4 | 54.5 | 0.76 |
| Cefotaxime | 51.1 | 43.7 | 0.85 |
| Aztreonam | NDb | <0.5 | —c |
| Moxalactam | 78.8 | 10.4 | 0.13 |
| Imipenem | 60 | 39.4 | 0.66 |
| Meropenem | 5.4 | 29.2 | 5.34 |
a
Standard deviations were within 10%.
b
ND, not determinable.
c
—, the hydrolysis parameter could not be calculated.