Kinetic analysis of M1 formation rates in incubations of DB289 with recombinant human P450 enzymes
Incubation mixtures contained 20 to 50 pmol/ml recombinant cytochrome P450, and DB289 ranging from 0.05 to 25 μM. Reactions were carried out at 37°C for the period of time indicated. M1 formation rates (mean of duplicate determinations) were determined by the LC/MS/MS method as described under Materials and Methods. Kinetic parameters were derived from the Hill equation. Results are arranged according to their maximum clearance values (CLmax).
Recombinant Human P450 Enzymes | |||||||
|---|---|---|---|---|---|---|---|
| 3A4 | 2D6 | 2E1 | 3A5 | ||||
| S50 (μM) | 3.7 | 2.8 | 2.9 | 4.7 | |||
| Vmax (nmol/min/nmol P450) | 0.72 | 0.35 | 0.03 | 0.06 | |||
| n (Hill coefficient) | 2.2 | 1.9 | 1.4 | 2.7 | |||
| CLmax (μl/min/pmol P450) | 0.098 | 0.063 | 0.007 | 0.006 | |||
| Incubation time (min) | 15 | 15 | 15 | 15 | |||
| Protein concentration (pmol P450/ml) | 50 | 20 | 50 | 50 | |||