TABLE 2

Kinetic parameters for hepatic microsomal methoxyresorufin (MR) and 7-benzyloxy-4-trifluoromethylcoumarin (BFC) metabolism in Cytb5(+/+) (wild-type) and Cytb5(−/−) (BCN) liver microsomes

Assays were performed using triplicate samples for each concentration of substrate as described under Materials and Methods. Standard deviations given are from the fit of the curve as calculated using the Michaelis-Menten equation (GraFit version 5; Erithacus Software, Horley, UK).

CompoundWTBCN
KmVmaxKmVmax
μMpmol/min/mgμMpmol/min/mg
MR0.039 ± 0.00135.5 ± 0.30.054 ± 0.00331.9 ± 0.5
BFC3.4 ± 0.9410 ± 2615.8 ± 2.491.8 ± 4.7