Kinetic parameters for serotonin O-glucuronide formation and diclofenac O-glucuronide formation by UGT1A6 in single and double expression systems
Data are mean ± S.D. of three independent determinations.
Clone | Serotonin O-Glucuronide Formation | Diclofenac O-Glucuronide Formation | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Km | Vmax | Vmax/Km | S50 | Vmax | Vmax/S50 | n | ||||||
| mM | nmol/min/unit | μl/min/unit | μM | pmol/min/unit | μl/min/unit | |||||||
| 1A6 | 4.6 ± 0.4 | 1.5 ± 0.1 | 0.3 ± 0.0 | 69.8 ± 1.8 | 28.4 ± 3.0 | 0.4 ± 0.0 | 1.8 ± 0.3 | |||||
| 1A1/1A6 | 4.4 ± 0.5 | 2.1 ± 0.1** | 0.5 ± 0.0 | 87.5 ± 20.8 | 88.0 ± 13.9** | 1.0 ± 0.1** | 1.8 ± 0.2 | |||||
| 1A4/1A6 | 3.7 ± 0.6 | 6.1 ± 0.4** | 1.7 ± 0.1** | 112.9 ± 25.6 | 75.8 ± 13.6** | 0.7 ± 0.1** | 2.1 ± 0.3 | |||||
↵** P < 0.01 compared with single expression system.