Table 1.
Steady-State Kinetic Parameters for different β-lactams by SPS-1, NDM-1 and SPM-1.
| Substratea | SPS-1 | SPM-112 | NDM-127, 28 | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Km(μM) | kcat(s-1) | kcat/Km (s-1/ μM) | Km (μM) | kcat (s1) | kcat/Km (s-1/ μM) | Km(μM) | kcat (s1) | kcat/Km (s-1/ μM) | |
| chromacef | 120±9 | 2.6±0.1 | 0.021 | Not available | 5.1±0.9 | 4.2 | 0.8 | ||
| ampicillin | Not observed | 72±3 | 120±2 | 1.6 | 22 | 15 | 0.66 | ||
| penicillin G | Not observed | Not available | 16 | 11 | 0.68 | ||||
| imipenem | 290±50 | 470±60 | 1.63 | 37±4 | 33±2 | 1 | 94 | 20 | 0.21 |
| meropenem | 170±30 | 520±50 | 3 | 280 ± 30 | 63 ± 3 | 0.22 | 49 | 12 | 0.25 |
| cephalothin | 110±20 | 3.1 ± 0.1 | 0.027 | 4±1 | 43±2 | 11.7 | 10 | 4 | 0.4 |
| cefuroxime | Not observed | 4 ± 1 | 37 ± 3 | 8.8 | 8 | 5 | 0.61 | ||
| cephalexin | Not observed | Not available | Not available | ||||||
a
Buffer was 50 mM HEPES, pH 7.5, containing 150 mM NaCI, and 10 μM ZnCI2