NC-Induced inhibition of E2 hydroxylation activity of CYP1A1, CYP1B1, and CYP1A2
Data represent the mean ± S.D. (n = 3).
| CYP1 Enzyme | E2 Hydroxylation Site | Km | Vmax | Vmax/Km | Activity Ratio (2-/4-) | IC50 | IC50 Ratio (2-/4-) |
| μM | nmol/min per nanomoles P450 | ml/min per nanomoles P450 | μM | ||||
| 1A1 | 2-OHE2 | 3.38 ± 0.69 | 6.91 ± 0.33 | 2.04 | 255 | 0.16 ± 0.004 | 0.64 |
| 4-OHE2 | 28.9 ± 11.5 | 0.22 ± 0.04 | 0.008 | 0.25 ± 0.04 | |||
| 1B1 | 2-OHE2 | 2.26 ± 0.30 | 0.45 ± 0.04 | 0.20 | 0.14 | 35.0 ± 6.44 | 4.23 |
| 4-OHE2 | 0.87 ± 0.16 | 1.21 ± 0.12 | 1.39 | 8.27 ± 2.40 | |||
| 1A2 | 2-OHE2 | 23.7 ± 4.06 | 50.6 ± 4.93 | 2.14 | 55 | 13.2 ± 5.56 | 2.47 |
| 4-OHE2 | 24.8 ± 4.78 | 0.97 ± 0.14 | 0.04 | 5.35 ± 0.62 |
2-/4-, 2-/4-hydroxylation.