TABLE 2.
Kinetics with β-lactams
The units of measure are μm for Km, s−1 for kcat, and μm−1 s−1 for kcat/Km.
| KPC-2 | R164S | Fold change (R164S/KPC-2) | |
|---|---|---|---|
| Ampicillin | |||
| Km | 51 ± 7 | 93 ± 10 | 1.8 |
| kcat | 26 ± 1 | 26 ± 1 | 1 |
| kcat/Km | 0.5 | 0.3 | 0.6 |
| Cephalothin | |||
| Km | 30 ± 6 | 40 ± 8 | 1.3 |
| kcat | 250 ± 20 | 280 ± 20 | 1.1 |
| kcat/Km | 8.3 | 7 | 0.8 |
| Nitrocefin | |||
| Km | 7 ± 0.7 | 8 ± 1 | 1.1 |
| kcat | 95 ± 10 | 66 ± 7 | 0.7 |
| kcat/Km | 13 | 8 | 0.6 |
| Cefoxitin | |||
| Km | 340 ± 100 | 260 ± 50 | 0.8 |
| kcat | 8 ± 1 | 3.2 ± 0.5 | 0.4 |
| kcat/Km | 0.024 | 0.012 | 0.5 |
| Cefotaxime | |||
| Km | 515 ± 160 | 260 ± 70 | 0.5 |
| kcat | 180 ± 20 | 90 ± 10 | 0.5 |
| kcat/Km | 0.35 | 0.35 | 1 |
| Ceftazidime | |||
| Km | 375 ± 60 | 180 ± 30 | 0.5 |
| kcat | 5.8 ± 0.6 | 3.5 ± 0.3 | 0.6 |
| kcat/Km | 0.015 | 0.019 | 1.3 |
| Cefepime | |||
| Km | >1000 | 900 ± 150 | NA |
| kcat | >6 | 6.1 ± 0.6 | NA |
| kcat/Km | 0.0067 | 0.0067 | 1 |
| Aztreonam | |||
| Km | 920 ± 160 | 700 ± 115 | 0.8 |
| kcat | 280 ± 30 | 120 ± 10 | 0.4 |
| kcat/Km | 0.30 | 0.17 | 0.6 |
| Imipenem | |||
| Km | 14 ± 2 | 11 ± 2 | 0.8 |
| kcat | 13 ± 1 | 5.5 ± 0.5 | 0.4 |
| kcat/Km | 1 | 0.5 | 0.5 |