TABLE 2.
Steady-state kinetic parameters for VIM-2 and VIM-20
| Substrate by Zn(II) concn | Parameter by metallo-β-lactamase |
|||||
|---|---|---|---|---|---|---|
| VIM-2 |
VIM-20 |
|||||
| KM (μM) | kcat (s−1) | kcat/KM (s−1 μM−1) | KM (μM) | kcat (s−1) | kcat/KM (s−1 μM−1) | |
| 10 μM | ||||||
| Meropenem | 5.0 ± 0.8 | 2.0 ± 0.1 | 0.4 | 9.9 ± 0.5 | 2.7 ± 0.1 | 0.27 |
| Ceftazidime | 90 ± 11 | 1.0 ± 0.1 | 0.01 | 105 ± 8 | 1.0 ± 0.1 | 0.01 |
| Ampicillin | 84 ± 7 | 125 ± 3 | 1.5 | 120 ± 9 | 176 ± 5 | 1.5 |
| Chromacef | 11 ± 2 | 27 ± 2 | 2.5 | 14 ± 1 | 49 ± 2 | 3.5 |
| 0.1 nM | ||||||
| Meropenem | 8 ± 1 | 1.6 ± 0.1 | 0.2 | 7.0 ± 0.5 | 2.0 ± 0.1 | 0.28 |
| Ceftazidime | 100 ± 10 | 0.76 ± 0.04 | 0.008 | 130 ± 10 | 0.68 ± 0.03 | 0.005 |
| Ampicillin | 82 ± 7 | 37.7 ± 0.9 | 0.46 | 49 ± 4 | 45.4 ± 0.8 | 0.93 |
| Chromacef | NDa | ND | ND | ND | ND | ND |
a
ND, not determined.