Kinetics of dex- and levomedetomidine glucuronidation by human liver microsomes The data are presented as mean ± S.E. of parameter fit. The assay conditions are detailed in the legend to Fig. 5.
Substrate | Glucuronide | Km1 | Km2 | Vmax1 | Vmax2 | Ksi | ||
|---|---|---|---|---|---|---|---|---|
| μM | pmol/min/mg | μM | ||||||
| Dexmedetomidine | DG1a | 6.61 ± 1.10 | 1930 ± 190 | 112 ± 7 | 2290 ± 140 | |||
| DG2a | 8.73 ± 1.23 | 1590 ± 380 | 59.0 ± 3.3 | 325 ± 43 | ||||
| Levomedetomidine | LG1b | 14.0 ± 0.4 | 2150 ± 28 | 860 ± 30 | ||||
|
| LG2c | >1000 | 121 ± 15 |
| ||||
↵ a The data were fitted to a two-enzyme equation (eq. 4; for further details, see Materials and Methods) using uniform weighting
↵ b The data were fitted to substrate inhibition equation (eq. 3; for further details, see Materials and Methods) using 1/v weighting
↵ c Kinetic constants could not be determined with confidence. In this case, the Vmax value indicates the highest observed glucuronidation rate at 2 mM substrate concentration