TABLE 1

Experimental conditions for measuring microsomal cytochrome P450 activity for enzyme inhibition studies

Ionization mode indicates the type of ionization (ESI) and the polarity (+ or −).

Enzyme	P450 Activity	Substrate Concentration	Protein	Incubation Time	Ionization Mode	Mass Transition Monitored	Internal Standard
		μM	mg/ml	min		amu
CYP1A2	Phenacetin O-dealkylation	40	0.1	5	ESI+^{^a}	152 → 110^{^a}	d₄-Acetaminophen
CYP2B6	Bupropion hydroxylation	50	0.1	5	ESI+	256 → 238	d₆-Hydroxybupropion
CYP2C8	Amodiaquine N-dealkylation	1.5	0.0125	5	ESI+	328 → 283	d₅-N-Desethylamodiaquine
CYP2C9	Diclofenac 4′-hydroxylation	6	0.1	5	ESI−	310 → 266	d₄-4′-Hydroxydiclofenac
CYP2C19	S-Mephenytoin 4′-hydroxylation	40	0.1	5	ESI−	233 → 190	d₃-4′-Hydroxymephenytoin
CYP2D6	Dextromethorphan O-demethylation	7.5	0.1	5	ESI+	258 → 157	d₃-Dextrorphan
CYP3A4	Testosterone 6β-hydroxylation	50	0.1	5	ESI+^{^b}	305 → 269^{^b}	d₃-6β-Hydroxytestosterone
CYP3A4	Midazolam 1′-hydroxylation	4	0.05	5	ESI+	342 → 324	d₄-1′-Hydroxymidazolam

amu, atomic mass units.
↵a Alternative analysis was conducted in ESI− mode with a monitored mass transition of 150 → 107.
↵b Alternative analysis was conducted in ESI− mode with a monitored mass transition of 303 → 287.