TABLE 2.
Steady-state kinetic parameters of purified KPC-2 and KPC-14 β-lactamases
| β-Lactam | KPC-2 |
KPC-14a
|
||||
|---|---|---|---|---|---|---|
| kcat (s−1) | Km (μM) | kcat/Km (μM−1·s−1) | kcat (s−1) | Km (μM) | kcat/Km (μM−1·s−1) | |
| Meropenem | 8.078 | 16.263 | 0.497 | NDb | ND | ND |
| Imipenem | 28.797 | 98.350 | 0.293 | 19.490 | 548.805 | 0.036 |
| Ceftazidime | 3.274 | 590.717 | 0.006 | 24.600 | 73.860 | 0.333 |
| Aztreonam | 12.601 | 2398.451 | 0.005 | 2.875 | 192.335 | 0.015 |
| Cefepime | 4.748 | 310.480 | 0.015 | 7.588 | 70.406 | 0.108 |
| Piperacillin | 7.709 | 793.526 | 0.010 | 1.084 | 45.767 | 0.024 |
| Cefazolin | 65.877 | 110.746 | 0.595 | 27.126 | 287.930 | 0.094 |
a
KPC-14 differs from KPC-2 by a 2-amino-acid 242Gly and 243Thr deletion.
b
ND, not detectable due to a low initial rate of hydrolysis.