Kinetic parameters for the glucuronidation of FA by human UGT2B7, UGT1A6, and UGT1A9 enzymes
Results are expressed as mean ± S.D. of two independent experiments performed in triplicate. Observed Vmax values were adjusted to relative protein expression; absolute values were 243 ± 3 for UGT2B7.1, 4.9 ± 4 for UGT1A6.1, and 16.2 ± 9 for UGT1A9.1.
| Allozymes | Apparent Km | Observed Vmax | -Fold versus *1 | Vmax/Km |
|---|---|---|---|---|
| μM | pmol/min/mg | μl/min/mg | ||
| UGT2B7 | ||||
| *1 | 126 ± 51 | 243 ± 3 | 2.1 ± 0.8 | |
| *2 (Tyr268) | 131 ± 76 | 136 ± 21 | 1.2 ± 0.5 | |
| UGT1A6 | ||||
| *1 | 222 ± 155 | 3.7 ± 3 | 0.02 ± 0.001 | |
| UGT1A9 | ||||
| *1 | 131 ± 45 | 12.0 ± 7 | 0.09 ± 0.02 | |
| *2 (Tyr3) | 121 ± 2 | 9.3 ± 1 | 0.08 ± 0.007 | |
| *3 (Thr33) | 271 ± 36 | 1.1 ± 0.07 | ↓ 10.9* | 0.004 ± 0.0002 |
↵* p value <0.05.