TABLE 3

IC50 values for various ligands as determined by enzyme inhibition assays

Enzyme inhibition was assessed using 7-methoxy-4-(trifluoromethyl)coumarin O-deethylation as described previously (Talakad et al., 2009). In brief, the reaction mixture contained 150 μM 7-methoxy-4-(trifluoromethyl)coumarin in the standard reconstitution system (P450/NADPH-cytochrome P450 reductase/cytochrome b5, 1:4:2) at 5 pmol of P450 in 50 mM Hepes, pH 7.4, 15 mM MgCl2, and 2% MeOH. The reaction was performed at 37°C for 5 min with 1 mM NADPH. Nonlinear regression analysis was performed to fit the data using a four-parameter logistic function to derive the IC50 values. Standard errors for fitting to the equation are shown.

LigandIC50
2B6dHY226HL264F
μM
4-Phenylpyridine5.6 ± 1.63.5 ± 1.35.7 ± 1.5
4-(4-Chlorophenyl)pyridine0.32 ± 0.120.29 ± 0.100.7 ± 0.28
4-(4-Chlorophenyl)imidazole0.26 ± 0.100.27 ± 0.080.37 ± 0.07
1-(4-Chlorophenyl)imidazole0.53 ± 0.0130.54 ± 0.140.37 ± 0.05
1-Benzylimdazole7.5 ± 1.26.2 ± 0.35.5 ± 1.2
4-Phenylimidazole1.4 ± 0.92.5 ± 0.51.7 ± 0.9