Kinetics parameters for in vitro (R) and (S) [14C]1,2-EPE glucuronidation
| Enantiomer | Km | Vmax | Km(R)/Km(S) | Vmax(R)/Vmax(S)2-a | V(R)/V(S)2-b | Vmax |
|---|---|---|---|---|---|---|
| μM | nmol/mg/min | μmol/min/g of liver2-c | ||||
| (R)1,2-EPE | 42 ± 1 | 0.082 ± 0.001 | 0.79 ± 0.02 | 0.27 ± 0.004 | 0.34 ± 0.02 | 6.3 |
| (S)1,2-EPE | 53 ± 42-150 | 0.31 ± 0.012-150 | 23.8 | |||
| Sum = 30.2 |
Kinetics parameters for (R) and (S)1,2-EPE glucuronide conjugation were calculated from Lineweaver-Burk curves (Fig. 4). Values are expressed as mean ± S.E.M. (n = 4–6).
↵2-150 Significantly different from (R)1,2-EPE formation, p < 0.05.
↵2-a Ratio of the formation rate of (R) versus (S)1,2-EPE glucuronide conjugates for 1,2-EPE concentrations very high compared with K mvalues.
↵2-b Ratio of the formation rate of (R) versus (S)1,2-EPE glucuronide conjugates for 1,2-EPE concentrations very low compared with K mvalues.
↵2-c One milligram of protein in S9 mixture corresponded to 13 mg of fresh liver.