Enzyme kinetic parameters of marker reactions of CYP2C9, 2C19, 2D6, and 3A4 in HLM
Marker Reaction | P450 | Km | Vmax |
|---|---|---|---|
| μM | pmol/min/mg protein | ||
| Diclofenac 4′-hydroxylation | 2C9 | 5.3 | 1396 |
| S-Mephenytoin 4′-hydroxylation | 2C19 | 20 | 30 |
| R-Omeprazole 5-hydroxylation | 2C19 | 1.1* | 29 |
| Bufuralol 1′-hydroxylation | 2D6 | 23 | 70 |
| Midazolam 1′-hydroxylation | 3A4 | 4.1 | 636 |
↵* R-Omeprazole 5-hydroxylation was catalyzed by two enzyme systems in HLM: a high-affinity enzyme system with Km1 = 1.1 μM and a low-affinity enzyme system with Km2 = 14 μM, respectively