Table 3. Steady-state kinetic parameters for the β-lactamase OXA-143.
Ceftazidime, cefotaxime, cefoxitin and aztreonam are not substrates of OXA-143. The K s values in parentheses are given in nM.
| Antibiotic | k cat (s−1) | K m (K s) (µM) | k cat/K m (M −1 s−1) |
|---|---|---|---|
| Ampicillin | 1400 ± 100 | 800 ± 100 | (1.7 ± 0.3) × 106 |
| Piperacillin | 120 ± 10 | 140 ± 20 | (8.6 ± 1.4) × 105 |
| Ticarcillin | >40 | >150 | (2.7 ± 0.2) × 105 |
| Oxacillin | >160 | >1000 | (1.8 ± 0.2) × 105 |
| Cephalothin | >2 | >200 | (9.0 ± 0.2) × 103 |
| Cefepime | >0.073 | >100 | (2.2 ± 0.2) × 102 |
| Imipenem | 1.3 ± 0.1 | 0.5 ± 0.1 (320 ± 40) | (2.6 ± 0.6) × 106 |
| Meropenem | 0.23 ± 0.01 | <0.5 (40 ± 5) | >4.6 × 105 |
| Doripenem | 0.20 ± 0.01 | <0.5 (28 ± 3) | >4.0 × 105 |
| Ertapenem | 0.17 ± 0.01 | <0.5 (12 ± 2) | >3.4 × 105 |