Table 5.
Steady state kinetic analysis for testosterone hydroxylation by P450 2B4dH/H226Y and mutants.
| P450 | 16α-OH | 16β-OH | 15α-OH | |||
|---|---|---|---|---|---|---|
| kcat (min-1) | Km (μM) | kcat (min-1) | Km (μM) | kcat (min-1) | Km (μM) | |
| 2B4dH/H226Y | 0.7 (0.1 )a | 175 (38) | -- | -- | -- | -- |
| F296A | 1.0 (0.2) | 96.0 (35) | -- | -- | -- | -- |
| I363A | 6.6 (0.3) | 30.4 (4.3) | 2.0 (0.1) | 32.6 (3.2) | 12.0 (0.7) | 28.4 (5.5) |
| V367A | -- | -- | 0.9 (0.2) | 180 (67) | -- | -- |
Results are the representative of at least two independent determinations. The variation between the experiments is ≤ 20%.
a
Standard errors for fit to Michaelis-Menten are shown in parenthesis