N-Oxygenation of TMA by human MBP-FMO3
The N-oxygenation of TMA was determined by monitoring the oxidation of NADPH associated with the N-oxygenation of TMA as described under Materials and Methods. Data are mean ± standard deviation.
Enzyme | n | Km | Vmax | Vmax/Km |
|---|---|---|---|---|
| μM | nmol/min/nmol | ml/min/nmol | ||
| FMO3 MBP | 9 | 8.2 ± 0.99 | 39.8 ± 4.03 | 4.87 ± 0.10 (100%) |
| Lys158-FMO3 MBP | 8 | 16.7 ± 2.11 | 29.6 ± 1.42 | 1.78 ± 0.16* (37%) |
| His132-FMO3 MBP | 6 | 26 ± 4.27 | 40.5 ± 4.77 | 1.57 ± 0.15* (32%) |
| His132, Lys158-FMO3 MBP | 6 | 11.2 ± 1.55 | 20 ± 0.62 | 1.82 ± 0.29* (37%) |
| Gly308-FMO3 MBP | 4 | 42 ± 12 | 18 ± 1.40 | 0.3 ± 0.10* (6%) |
| Lys158, Gly308-FMO3 MBP | 9 | 23 ± 2.6 | 7.7 ± 0.72 | 0.34 ± 0.60* (7%) |
|
Pro360-FMO3 MBP
|
9
|
10.6 ± 3.5
|
220 ± 21.5
|
21.8 ± 5.04* (448%)
|
↵* p < 0.05 compared to the result obtained for wild-type MBP-FMO3.