Kinetic parameters for 4MU, 1NP and AZT glucuronidation by UGT2B7
Kinetic parameters are shown as mean ± S.E. of parameter fit. Values for 4MU and 1NP use the Hill equation; those for AZT use the Michaelis-Menten equation.
Substrate | Michaelis-Menten or Hill Equation | Two-site Model | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Km or S50 | Vmax | nH | Ks | Vmax | α | |||||
| μM | pmol/min · mg | μM | pmol/min · mg | |||||||
| 4MU | 393 ± 28 | 1018 ± 44 | 1.7 ± 0.15 | 1441 ± 126 | 1090 ± 36 | 0.09 | ||||
| 1NP | 158 ± 4 | 497 ± 6 | 1.5 ± 0.05 | 623 ± 123 | 487 ± 18 | 0.06 | ||||
| AZT | 376 ± 12 | 43 ± 0.45 |
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nH, Hill coefficient; α, interaction factor from two-site model (Fig. 1, eq. 3) with β = 2