TABLE 2.
Steady-state kinetic parameters of the β-lactamase FRI-1 and comparison of parameters obtained for the β-lactamases NMC-A (24), IMI-1 (13), SME-1 (11), KPC-2 (16), SFC-1 (28), and GES-4 (15)
| Parameter | β-Lactam | Valuea |
||||||
|---|---|---|---|---|---|---|---|---|
| FRI-1 | NMC-A | IMI-1 | SME-1 | KPC-2 | SFC-1 | GES-4 | ||
| kcat (s−1) | Benzylpenicillin | 1,060 | 260 | 36 | 19.3 | 63 | NA | 130 |
| Amoxicillin | >17,000 | 816 | 190 | 181 | NA | NA | 19 | |
| Ticarcillin | 120 | 81 | NA | NA | NA | NA | NA | |
| Piperacillin | >2,600 | NA | 6.1 | NA | NA | NA | NA | |
| Cefotaxime | >220 | 286 | 3.4 | <0.98 | 17 | 8.3 | 17 | |
| Cefepime | 28 | NA | NA | NA | 12 | NA | NA | |
| Ceftazidime | − | − | <0.01 | NA | 0.5 | 2.1 | 2.5 | |
| Aztreonam | >8,300 | 707 | 51 | 108 | 66 | 162 | NA | |
| Imipenem | 1,790 | 1,040 | 89 | 104 | 31 | 54 | 7.7 | |
| Ertapenem | 150 | NA | NA | NA | NA | NA | NA | |
| Meropenem | 46 | 12 | 10 | 8.9 | 3.6 | 6.5 | NA | |
| Km (μM) | Benzylpenicillin | 567 | 28 | 64 | 16.7 | 30 | NA | 160 |
| Amoxicillin | >5,000 | 90 | 780 | 488 | NA | NA | 62 | |
| Ticarcillin | 393 | 152 | NA | NA | NA | NA | NA | |
| Piperacillin | >3,000 | NA | 13 | NA | NA | NA | NA | |
| Cefotaxime | >5,000 | 956 | 190 | − | 100 | 89 | 700 | |
| Cefepime | 3,400 | NA | NA | NA | 540 | NA | NA | |
| Ceftazidime | − | − | 270 | − | 230 | 52 | 1,500 | |
| Aztreonam | >5,000 | 125 | 93 | 259 | 420 | 484 | − | |
| Imipenem | 1,614 | 92 | 170 | 202 | 90 | 82 | 4.7 | |
| Ertapenem | 98 | NA | NA | NA | NA | NA | NA | |
| Meropenem | 70 | 4.35 | 26 | 13.4 | 13 | 26 | NA | |
| kcat/Km (mM−1/s) | Benzylpenicillin | 1,870 | 9,300 | 560 | 1,160 | 2,100 | NA | 780 |
| Amoxicillin | 3,400 | 9,060 | 240 | 370 | NA | NA | 310 | |
| Ticarcillin | 305 | 530 | NA | NA | NA | NA | NA | |
| Piperacillin | 867 | NA | 470 | NA | NA | NA | NA | |
| Cefotaxime | 44 | 300 | 18 | − | 170 | 93 | 24 | |
| Cefepime | 8 | NA | NA | NA | 22 | NA | NA | |
| Ceftazidime | − | 52 | 0.02 | − | 2.1 | 40 | 1.7 | |
| Aztreonam | 1,660 | 5,600 | 550 | 420 | 160 | 3.5 | − | |
| Imipenem | 1,109 | 11,000 | 520 | 520 | 340 | 660 | 81 | |
| Ertapenem | 1,531 | NA | NA | NA | 280 | 250 | NA | |
| Meropenem | 657 | 2,700 | 380 | 660 | NA | NA | NA | |
a
−, no detectable hydrolysis; NA, no data available.