Steady-state kinetics: effect of b5 on H2O2-supported activity of CYP3A4 wild-type and active site mutants Data are representative of at least two independent experiments. The variation between the experiments is ≤15%.
P450s | kcat | S50 | n | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Nil | b5 | Nil | b5 | Nil | b5 | ||||
| min–1 | μM | ||||||||
| Wild-Type (15)a | 1.44 (0.02)b | 3.58 (0.01) | 71.7 (2.2) | 50.6 (0.5) | 1.86 (0.11) | 1.56 (0.03) | |||
| S119A (12) | 0.77 (0.02) | 3.09 (0.14) | 88.4 (4.0) | 116 (7.2) | 2.04 (0.41) | 1.71 (0.22) | |||
| S119W (10) | 1.31 (0.08) | 1.19 (0.06) | 195 (21) | 169 (14) | 1.01 (0.03) | 1.04 (0.02) | |||
| I301A (11) | 0.48 (0.01) | 2.56 (0.05) | 93.3 (3.0) | 160 (4.4) | 1.56 (0.04) | 1.43 (0.04) | |||
| I301F (6) | 0.61 (0.00) | 0.72 (0.02) | 100 (1.4) | 82.0 (4.7) | 2.09 (0.07) | 1.45 (0.14) | |||
| A305F (10) | 1.41 (0.05) | 0.68 (0.03) | 173 (7.1) | 135 (8.5) | 1.64 (0.12) | 1.53 (0.13) | |||
| I369F (12) | 0.98 (0.03) | 3.04 (0.03) | 122 (4.1) | 159 (2.7) | 1.85 (0.13) | 1.01 (0.02) | |||
| A370F (12) | 0.56 (0.03) | 0.82 (0.05) | 146 (7.6) | 146 (15) | 2.25 (0.29) | 1.24 (0.20) | |||
| L373F (3.0) | 3.02 (0.22) | 17 (1.0) | 212 (14) | 190 (11) | 1.78 (0.22) | 1.55 (0.15) | |||