Characterization of human liver tissues (n = 164) for selective substrates of P450 enzymes
The values are expressed as pmol product/mg microsomal protein × min.
| P450 Activity | Enzyme Activity | Minimum | Maximum | Cutoff Values | |
|---|---|---|---|---|---|
| PM-IM First Quartile | IM-EM Third Quartile | ||||
| Median ± QD | |||||
| CYP1A2 | |||||
| Phenacetin O-dealkylation | 155.9 ± 110.75 | 0 | 1107.1 | 60.2 | 281.7 |
| CYP2B6 | |||||
| Mephenytoin N-demethylation | 35.7 ± 22.20 | 6.47 | 538.3 | 22.3 | 66.7 |
| CYP2C9 | |||||
| Tolbutamide 4-hydroxylation | 218.2 ± 100.55 | 0 | 1056.0 | 104.4 | 305.6 |
| CYP2C19 | |||||
| Mephenytoin 4′-hydroxylation | 25.2 ± 19.15 | 0 | 342.9 | 11.9 | 50.2 |
| CYP2D6 | |||||
| Dextromethorphan O-demethylation | 261.0 ± 162.0 | 0 | 1461.0 | 140.6 | 464.6 |
| CYP3A4/5 | |||||
| Nifedipine oxidation | 414.2 ± 272.0.25 | 3.79 | 2861.5 | 231.8 | 776.3 |
| Midazolam 4-hydroxylation | 175.2 ± 141.25 | 11.9 | 1180.0 | 101.1 | 383.6 |
| Midazolam 1′-hydroxylation | 107.7 ± 77.4 | 3.42 | 630.7 | 72.8 | 227.6 |
PM, poor metabolizer; IM, intermediate metabolizer; EM, extensive metabolizer.