Determining the IC₅₀ Values for Vorozole and Letrozole, on a Series of Human Liver Cytochrome P450s, to Help Determine the Binding Site of Vorozole in the Liver

Table 2

IC₅₀ values (±SEM) for vorozole and letrozole on CYP1A1, CYP1A2, CYP2A6, CYP3A4, and CYP19A1 for 3 replicate assays.

	Vorozole (M)	Letrozole (M)	Fold difference
CYP1A1	0.469 ± 0.031	69.8 ± 5.3	149
CYP1A2	321 ± 49	332 ± 195	1.03
CYP2A6	24.4 ± 3.6	106 ± 34	4.34
CYP3A4	98.1 ± 15.6	<10% @ 1 mM	>10
CYP19A1	0.00417 ± 0.00019	0.00727 ± 0.00070	1.73