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 1

Fluorometric enzyme assay conditions for recombinant cytochrome P450s (CYPs). 3-Cyano-7-ethoxycoumarin (CEC), 3-cyano-7-hydroxycoumarin (CHC), 7-hydroxycoumarin (HC), 7-benzyloxy-4-(trifluoromethyl)coumarin (BFC), 7-hydroxy-4-(trifluoromethyl)coumarin (HFC), 7-methoxy-4-(trifluoromethyl)coumarin (MFC), excitation wavelength (), and emission wavelength ().

Enzyme	Enzyme amount; (pmol)	Substrate	Substrate concentration (M)	Product	(nm)	(nm)
CYP1A1	1	CEC	5	CHC	410	450
CYP1A2	0.5	CEC	5	CHC	410	450
CYP2A6	1	Coumarin	3	HC	330	460
CYP3A4	1	BFC	50	HFC	409	530
CYP19A1	1.5	MFC	100	HFC	409	530