TABLE 2.
Kinetic parameters of β-lactamases TEM-154, TEM-12, TEM-33, and TEM-1a
| β-Lactam | TEM-154 |
TEM-12 |
TEM-33 |
TEM-1b |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| kcat(s−1) | Km (μM) | kcat/Km (μM−1·s−1) | kcat(s−1) | Km (μM) | kcat/Km (μM−1·s−1) | kcat(s−1) | Km (μM) | kcat/Km (μM−1·s−1) | kcat(s−1) | Km (μM) | kcat/Km (μM−1·s−1) | |
| Benzylpenicillin | 357 | 25 | 14.3 | 80 | 7 | 11 | 150 | 15 | 10 | 1200 | 25 | 48 |
| Amoxicillin | 196 | 21 | 9.3 | 60 | 7.5 | 8 | 111 | 23 | 5 | 920 | 26 | 35.4 |
| Ticarcillin | 143 | 90 | 1.6 | 19 | 12 | 1.6 | 2 | 7 | 0.2 | 115 | 10 | 11.5 |
| Piperacillin | 465 | 64 | 7.3 | 89 | 15 | 6 | 83 | 15 | 6 | 987 | 45 | 21.9 |
| Cephalothin | 42 | 79 | 0.5 | 46 | 327 | 0.1 | 5 | 317 | 0.01 | 122 | 250 | 0.5 |
| Cefuroxime | 1.2 | 16 | 0.08 | 1.6 | 81 | 0.02 | <0.1 | ND | ND | <0.1 | ND | ND |
| Ceftazidime | 39 | 166 | 0.2 | 11 | 254 | 0.04 | <0.1 | ND | ND | <0.1 | ND | ND |
| Cefotaxime | 4.9 | 83 | 0.06 | 11 | 320 | 0.03 | <0.1 | ND | ND | 1.2 | ND | ND |
| Aztreonam | 2.5 | 56 | 0.04 | 2 | 247 | 0.008 | <0.1 | ND | ND | <0.1 | ND | ND |
a
ND, not determined. The standard deviations for the results of the analysis were ≤15%.
b
Data are from the work of Sirot et al. (21)