TABLE 3.
Kinetic parameters of purified IMP-19a
| Substrate | kcat (s−1) | Km (μM) | kcat/Km (μM−1 s−1) |
|---|---|---|---|
| Benzylpenicillin | 1,011 | 206 | 4.91 |
| Amoxicillin | 456 (23) | 207 (110) | 2.20 (0.21) |
| Ticarcillin | 683 (252) | 140 (700) | 4.88 (0.36) |
| Piperacillin | 41.2 | 148 | 0.28 |
| Cephalothin | 11.0 | 76 | 0.14 |
| Cefuroxime | 16.4 | 95 | 0.17 |
| Cefoxitin | 9.7 (7) | 33 (7) | 0.29 (1.0) |
| Cefotaxime | 20.1 | 61 | 0.33 |
| Cefpirome | 14.3 | 48 | 0.30 |
| Ceftazidime | 6.4 (21) | 20 (111) | 0.32 (0.19) |
| Imipenem | 26.5 (22) | 100 (24) | 0.26 (0.92) |
| Meropenem | 1.0 (1) | 7 (0.3) | 0.14 (3.3) |
| Aztreonam | <0.1 | NDb | ND |
a
Values in parentheses are those for IMP-2 (14).
b
ND, not determined.