Table 2.
Kinetic parameters for wild type and mutant CTX-M enzymes
| β-Lactamase | Parameter | Antibiotica |
|
|---|---|---|---|
| CTX | CAZ | ||
| CTX-M-14 | kcat (s−1) | 203 ± 13.4 | ND |
| Km (μm) | 72 ± 6.7 | >500 | |
| kcat/Km (s−1 m−1) | 2.8 ± 0.3 | 0.001 ± 0.0007 | |
| N106S | kcat (s−1) | ND | ND |
| Km (μm) | >500 | >500 | |
| kcat/Km (s−1 m−1) | 0.6 ± 0.02 | 0.0006 ± 4.5E-05 | |
| D240G | kcat (s−1) | 321 ± 46.2 | ND |
| Km (μm) | 52 ± 8.6 | >500 | |
| kcat/Km (s−1 m−1) | 6.2 ± 1.4 | 0.013 ± 0.0007 | |
| N106S/D240G | kcat (s−1) | 475 ± 59 | ND |
| Km (μm) | 310 ± 10 | >500 | |
| kcat/m (s−1 m−1) | 1.5 ± 0.2 | 0.003 ± 2E-0.5 | |
| N104A | kcat (s−1) | ND | ND |
| Km (μm) | >500 | >500 | |
| kcat/Km (s−1 m−1) | 0.2 ± 0.01 | 0.0001 ± 1.4E-06 | |
a CTX is cefotaxime; CAZ is ceftazidime; ND is not determined.