Table 1.
Antibiotic degradation kinetics of ribaxamase and P2A. Steady-state KM and kcat values for the indicated beta-lactam antibiotics were determined by measuring substrate hydrolysis under initial rate conditions with Hanes linearization of the Michalis-Menten equation. Relative antibiotic degradation efficiency based on the E. coli growth assay is displayed in the last column for comparison.
| Antibiotic | SYN-004 (Ribaxamase) | P2A | E. coli Assay | ||||
|---|---|---|---|---|---|---|---|
| KM | Kcat | Kcat/KM | KM | Kcat | Kcat/KM | ||
| mM | s−1 | M−1 s−1 (× 10−3) | mM | s−1 | M−1 s−1 (× 10−3) | ||
| Ampicillin | 161 | 2160 | 13417 | 942 | 1114 | 1183 | ribaxamase > P2A |
| Pipercillin | 53 | 816 | 15396 | 372 | 1049 | 2820 | ribaxamase = P2A |
| Ceftriaxone | 38 | 83 | 2184 | 68 | 95 | 1397 | P2A > ribaxamase |
| Cefotaxime | 21 | 36 | 1714 | 66 | 479 | 7258 | P2A > ribaxamase |
| Cefazoline | 37 | 192 | 5189 | 39 | 6 | 154 | Ribaxamase > P2A |
| Cefoperazone | 2 | 17 | 8500 | 82 | 338 | 4122 | P2A > ribaxamase |
| Cefuroxime | 277 | 35 | 126 | 27 | 221 | 8185 | P2A > ribaxamase |
| Imipenem | Not active | Not active | 337 | 1480 | 4392 | P2A | |
| Meropenem | Not active | Not active | 410 | 480 | 1171 | P2A | |