TABLE 3.
Kinetic constants determined for wild-type XplA-heme and mutants determined by measurement consumption of RDX by HPLC (kcat and Km) and by spectrophotometry (KD) as detailed under “Experimental Procedures”
| Enzyme | KD | Km | kcat | kcat/Km |
|---|---|---|---|---|
| μm | μm | s−1 | μm−1·s−1 ×103 | |
| Wild type | 11.44 ± 0.39 | 10.23 ± 0.90 | 3.33 ± 0.07 | 325.0 |
| A395T | NDa | 39.85 ± 6.86 | 0.07 ± 0.01 | 1.7 |
| Q438A | 67.28 ± 4.83 | 17.80 ± 1.80 | 0.35 ± 0.01 | 19.6 |
| M322L | 7.97 ± 0.94 | 12.04 ± 0.70 | 3.55 ± 0.05 | 295.0 |
| M318L | 34.32 ± 4.30 | 35.75 ± 13.69 | 0.57 ± 0.08 | 15.9 |
| M394L | 20.46 ± 0.47 | 4.94 ± 1.14 | 0.73 ± 0.03 | 148.0 |
a ND, not determined.