TABLE 4.
Kinetic parameters of various β-lactam antibiotics for the KPC-2 β-lactamase
| Substrate | kcat (s−1)a | Km (μM)a | kcat/Km (mM−1·s−1) |
|---|---|---|---|
| Benzylpenicillin | 45 ± 2 | 44 ± 3 | 1,000 |
| Ampicillin | 20 ± 1 | 29 ± 2 | 700 |
| Ticarcillin | NDb | ND | ND |
| Piperacillin | 40 ± 3 | 51 ± 1 | 800 |
| Cephalothin | 106 ± 5 | 141 ± 3 | 750 |
| Cefuroxime | 66 ± 6 | 160 ± 2 | 410 |
| Cefotaxime | 66 ± 3 | 174 ± 1 | 380 |
| Ceftazidime | ND | ND | ND |
| Aztreonam | 3 ± 0.1 | 35 ± 2 | 900 |
| Cefpirome | 12 ± 0.1 | 251 ± 20 | 500 |
| Imipenem | 20 ± 1 | 88 ± 8 | 230 |
a
Standard deviation values are indicated after the kinetic parameter values.
b
ND, not determinable.