Kinetic parameters for various CYP3A4 substrates
| Human Liver Microsomes | CYP3A4/P-450 Reductase | |||
|---|---|---|---|---|
| Km | Vmax | Km | Vmax | |
| μM | nmol/min/mg | μM | nmol/min/mg | |
| Testosterone 6β-hydroxylation | 83 ± 14 | 12.05 ± 0.07 | 56 ± 9 | 3.50 ± 0.71 |
| Terfenadinet-butyl hydroxylation | 15 ± 8 | 0.46 ± 0.15 | 14 ± 1 | 0.11 ± 0.04 |
| Midazolam 1′-hydroxylation | 14 ± 1 | 5.50 ± 2.12 | 3 ± 1 | 0.91 ± 0.18 |
| Nifedipine oxidation | 47 ± 10 | 3.36 ± 0.46 | ND1-a | ND1-a |
Kinetic parameters were determined in duplicate with one human liver microsomal preparation or microsomal preparations from human B lymphoblastoid cells expressing recombinant CYP3A4 and P-450 reductase. Experiments were carried out over a period of several months under identical conditions.
↵1-a ND: Not determined.