Table 2. Steady-State Kinetic Parameters for the Hydrolysis of Carbapenems by GES Enzymes.
| enzyme | parameter | meropenem | ertapenem | doripenem |
|---|---|---|---|---|
| GES-1 | kcat (s–1) | 0.00094 ± 0.00004 | 0.00076 ± 0.00002 | 0.00063 ± 0.00003 |
| Km (μM) | 0.9 ± 0.5 | 2.2 ± 0.4 | 1.0 ± 0.7 | |
| kcat/Km (M–1 s–1) | (1.0 ± 0.6) × 103 | (3.5 ± 0.6) × 102 | (6.3 ± 4.4) × 102 | |
| Ks (μM) | 0.34 ± 0.04 | 0.25 ± 0.03 | 0.18 ± 0.02 | |
| GES-2 | kcat (s–1) | 0.0033 ± 0.0002 | 0.0062 ± 0.0002 | 0.0024 ± 0.0002 |
| Km (μM) | 4.1 ± 0.8 | 4.0 ± 0.6 | 5 ± 1 | |
| kcat/Km (M–1 s–1) | (8.1 ± 1.6) × 102 | (1.6 ± 0.2) × 103 | (4.4 ± 1.2) × 102 | |
| Ks (μM) | 1.2 ± 0.1 | 1.7 ± 0.2 | 1.0 ± 0.1 | |
| GES-5 | kcat (s–1) | 0.076 ± 0.004 | 0.053 ± 0.002 | 0.046 ± 0.001 |
| Km (μM) | 1.0 ± 0.7 | 2.0 ± 0.6 | 0.9 ± 0.2 | |
| kcat/Km (M–1 s–1) | (7.6 ± 5.3) × 104 | (2.7 ± 0.8) × 104 | (5 ± 1) × 104 | |
| Ks (μM) | 0.32 ± 0.08 | 0.25 ± 0.03 | 0.25 ± 0.03 |