TABLE 2.
Substrate | VIM-15
|
VIM-16
|
VIM-2
|
||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
kcat (s−1) | Relativebkcat | Km (μM) | kcat/Km (s−1 μM−1) | Relativebkcat/Km | kcat (s−1) | Relativebkcat | Km (μM) | kcat/Km (s−1 μM−1) | Relativebkcat/Km | kcat (s−1) | Relativebkcat | Km (μM) | kcat/Km (s−1 μM−1) | Relativebkcat/Km | |
Cephaloridine | 190 ± 4 | 100 | 83 ± 2 | 2.3 | 100 | 89 ± 2 | 100 | 1400 ± 53 | 0.064 | 100 | 120 ± 5 | 100 | 1400 ± 6 | 0.086 | 100 |
Benzylpenicillin | 240 ± 3 | 130 | 25 ± 0.5 | 9.6 | 420 | 230 ± 24 | 260 | 450 ± 8 | 0.51 | 800 | 73 ± 0.4 | 61 | 150 ± 1 | 0.49 | 570 |
Cefepime | 9.5 ± 0.1 | 5.0 | 130 ± 2 | 0.076 | 3.3 | 0.31 ± 0.03 | 0.35 | 210 ± 1 | 0.0015 | 2.3 | 0.38 ± 0.02 | 0.32 | 110 ± 6 | 0.0035 | 4.1 |
Ceftazidime | 1.0 ± 0.04 | 0.53 | 37 ± 2 | 0.027 | 1.2 | 0.22 ± 0.00 | 0.25 | 150 ± 2 | 0.0014 | 2.2 | 0.23 ± 0.01 | 0.19 | 150 ± 6 | 0.0015 | 1.7 |
Cefotaxime | 90 ± 7 | 47 | 13 ± 1 | 6.9 | 300 | 81 ± 0.2 | 91 | 240 ± 9 | 0.34 | 530 | NT | NT | NT | NT | NT |
Imipenem | 61 ± 2 | 32 | 7.3 ± 0.5 | 8.4 | 370 | 45 ± 2 | 51 | 89 ± 2 | 0.51 | 800 | 20 ± 0.3 | 17 | 60 ± 2 | 0.33 | 380 |
Meropenem | 6.5 ± 0.05 | 3.4 | 3.4 ± 0.5 | 1.9 | 83 | 8.4 ± 0.3 | 9.4 | 120 ± 5 | 0.070 | 110 | 2.1 ± 0.1 | 1.8 | 40 ± 2 | 0.053 | 62 |
Aztreonamc | ≤0.031 | ≤0.016 | ND | ND | ND | ≤0.11 | ≤0.12 | ND | ND | ND | NT | NT | NT | NT | NT |
NT, not tested; ND, not determined as hydrolysis was too slow to determine Km.
The cephaloridine value was taken as 100%.
Hydrolysis of aztreonam was very slow; Vmax was estimated as 2 times the maximum hydrolysis rate observed.