Kinetics parameters for in vitro [14C]1,2-DEB hydroxylation
| Enantiomer | Km | Vmax | Km(R)/Km(S) | Vmax(R)/Vmax(S)1-a | V(R)/V(S)1-b | Vmax |
|---|---|---|---|---|---|---|
| μM | nmol/mg/min | μmol/min/g of liver1-c | ||||
| (R)1,2-EPE | 1081 ± 93 | 6.1 ± 0.5 | 2.6 ± 0.06 | 3.2 ± 0.07 | 1.2 ± 0.006 | 0.47 |
| (S)1,2-EPE | 410 ± 91-150 | 1.9 ± 0.041-150 | 0.15 | |||
| Sum = 0.62 |
Kinetics parameters for (R) and (S)1,2-EPE formation were calculated from Lineweaver-Burk curves (Fig. 3). Values are expressed as mean ± S.E.M. (n = 5).
↵1-150 Significantly different from (R)1,2-EPE formation, p < 0.05.
↵1-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.
↵1-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.
↵1-c One milligram of protein in S9 mixture corresponded to 13 mg of fresh liver.