Table 2.
Substrate profile of the BPU-1 β-lactamase
| Antimicrobial | kcat (s−1) | Km (µM) | kcat/Km (M−1s−1) |
|---|---|---|---|
| Ampicillin | 56 ± 2 | 27 ± 3 | (2.1 ± 0.3) × 106 |
| Piperacillin | 60 ± 2 | 15 ± 2.5 | (3.9 ± 0.6) × 106 |
| Ticarcillin | 39 ± 2 | 34 ± 5 | (1.1 ± 0.2) × 106 |
| Oxacillin | 19 ± 1 | 4 ± 1 | (4.7 ± 1.4) × 106 |
| Cephalosporin C | 0.093 ± 0.003 | 200 ± 16 | (4.7 ± 0.4) × 102 |
| Cephalothin | 0.70 ± 0.03 | 60 ± 6 | (1.2 ± 0.1) × 104 |
| Ceftazidime1 | >0.9 | >150 | (8.1 ± 0.6) × 103 |
| Cefotaxime1 | >0.7 | >150 | (7.2 ± 1.0) × 103 |
| Cefepime1 | >13 | >180 | (1.2 ± 0.3) × 105 |
| Aztreonam | 0.51 ± 0.02 | 35 ± 5 | (1.5 ± 0.2) × 104 |
| Imipenem | 0.26 ± 0.02 | 6.6 ± 0.8 | (3.9 ± 0.6) × 104 |
| Meropenem | 0.014 ± 0.001 | 4.2 ± 0.4 | (3.3 ± 0.4) × 103 |
| Doripenem | 0.014 ± 0.02 | 4.1 ± 1.1 | (3.4 ± 0.9) × 103 |
| Nitrocefin | 830 ± 30 | 82 ± 8 | (1.0 ± 0.1) × 107 |
Only the lower limit for kcat and Km could be measured