TABLE 8

Summary of mean ±S.E. inhibitor potencies for 12 human cytochrome P450 activities in pooled human liver microsomes and recombinant heterologously expressed P450 enzymes

Enzyme	Assay	Inhibitor	IC₅₀
Enzyme	Assay	Inhibitor			Pooled human liver microsomes	Recombinant heterologously expressed enzyme
			μM
CYP1A2	Phenacetin O-deethylase	Furafylline	1.76 ± 0.28	1.54 ± 0.16
CYP2A6	Coumarin 7-hydroxylase	Tranylcypromine	0.449 ± 0.073	0.895 ± 0.262
CYP2B6	Bupropion hydroxylase	PPP	7.74 ± 0.47	2.02 ± 0.19
CYP2C8	Amodiaquine N-deethylase	Quercetin	3.06 ± 0.31	3.33 ± 0.20
CYP2C9	Diclofenac 4′-hydroxylase	Sulfaphenazole	0.272 ± 0.031	0.169 ± 0.004
CYP2C9	Tolbutamide hydroxylase	Sulfaphenazole	0.277 ± 0.023	0.200 ± 0.011
CYP2C19	(S)-Mephenytoin 4′-hydroxylase	(+)-N-3-Benzylnirvanol	0.414 ± 0.035	0.161 ± 0.019
CYP2D6	Dextromethorphan O-demethylase	Quinidine	0.0579 ± 0.0043	1.78 ± 0.04
CYP2E1	Chlorzoxazone 7-hydroxylase	Tranylcypromine	8.94 ± 1.54	17.1 ± 2.8
CYP3A	Felodipine dehydrogenase	Ketoconazole	0.0163 ± 0.0018	0.166 ± 0.023^a
				0.374 ± 0.031^b
CYP3A	Midazolam 1′-hydroxylase	Ketoconazole	0.0187 ± 0.0025	0.0619 ± 0.0089^a
				0.105 ± 0.012^b
CYP3A	Testosterone 6β-hydroxylase	Ketoconazole	0.0261 ± 0.0030	0.0746 ± 0.0204^a
				0.492 ± 0.178^b

↵ a Mean ± S.E. for recombinant CYP3A4
↵ b Mean ± S.E. for recombinant CYP3A5