Kinetic parameters for estradiol 3-O-glucuronide formation and bilirubin O-glucuronide formation by UGT1A1 in single and double expression systems
Data are mean ± S.D. of three independent determinations.
Clone | Estradiol 3-O-Glucuronide Formation | Bilirubin O-Glucuronide Formation | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| S50 | Vmax | Vmax/S50 | n | S50 | Vmax | Vmax/S50 | n | |||||||
| μM | pmol/min/unit | μl/min/unit | μM | pmol/min/unit | μl/min/unit | |||||||||
| 1A1 | 8.7 ± 0.3 | 975.0 ± 27.4 | 112.1 ± 1.8 | 1.7 ± 0.1 | 2.6 ± 0.4 | 223.5 ± 9.8 | 88.9 ± 17.0 | 2.7 ± 0.1 | ||||||
| 1A1/1A4 | 5.7 ± 0.1** | 498.4 ± 1.9** | 87.5 ± 1.8** | 1.9 ± 0.2 | 1.2 ± 0.1** | 256.3 ± 36.4 | 216.1 ± 46.2* | 2.6 ± 0.1 | ||||||
| 1A1/1A6 | 7.1 ± 0.1** | 917.3 ± 4.2** | 128.6 ± 1.0** | 1.9 ± 0.2 | 1.1 ± 0.2** | 303.7 ± 33.3* | 293.5 ± 71.0** | 3.0 ± 0.8 | ||||||
*P < 0.05; **P < 0.01 compared with single expression system.