Table 2.
Oxidation of nicotinamide cofactors by HpxL and PcxL
The apparent rate in the presence/absence of different flavin cofactors and 2AEPn is shown. 2AEPn* = rate in the presence of 2AEPn after subtraction of the uncoupled rate (i.e. before the addition of 2AEPn). 2AEPn was used at a concentration of 5 mm, whereas FAD and FMN were used at 50 μm and NADPH and NADH at 300 μm. Each experiment was completed in triplicate.
| Cofactor(s) | Substrate |
kobs |
|
|---|---|---|---|
| HpxL | PcxL | ||
| s−1 × 10−3 | |||
| NADPH | None | 2.7 ± 0.4 | 14.4 ± 0.7 |
| 2AEPn | 7.2 ± 0.6 | 232 ± 8 | |
| NADPH/FAD | None | 12.5 ± 0.1 | 21 ± 1 |
| 2AEPn | 23.2 ± 0.7 | 310 ± 20 | |
| 2AEPn* | 10.7 ± 0.6 | 290 ± 20 | |
| NADPH/FMN | None | 5.2 ± 0.5 | 14.3 ± 0.7 |
| 2AEPn | 10.0 ± 0.2 | 210 ± 20 | |
| 2AEPn* | 4.8 ± 0.7 | 200 ± 20 | |
| NADH | None | 5.5 ± 0.1 | 24 ± 1 |
| 2AEPn | 1.7 ± 0.2 | 29 ± 2 | |
| NADH/FAD | None | 14 ± 2 | 85 ± 5 |
| 2AEPn | 15.0 ± 0.7 | 83 ± 5 | |
| 2AEPn* | 0.1 ± 0.1 | 0 ± 3 | |
| NADH/FMN | None | 5.9 ± 0.3 | 26.6 ± 0.2 |
| 2AEPn | 7.0 ± 0.4 | 27 ± 4 | |
| 2AEPn* | 1.0 ± 0.2 | 1 ± 4 | |