Table 2

Metabolism of warfarin in incubations with human liver microsomes^2-a

Warfarin	Formation of 10-Hydroxywarfarin		Formation of 4′-Hydroxywarfarin
Warfarin	K_m 2-b	V_max 2-b	V_max/K_m× 10³	K_m 2-b	V_max 2-b	V_max/K_m× 10³
	mM	pmol/min/mg	ml/min/mg	mM	pmol/min/mg	ml/min/mg
R	0.24 ± 0.04	176 ± 12	0.73	0.15 ± 0.03	7 ± 1	0.046
S	0.24 ± 0.05	18 ± 2	0.075	0.13 ± 0.04	14 ± 1	0.11
Racemic	0.59 ± 0.09	46 ± 4	0.077	0.29 ± 0.08	4 ± 0	0.013

↵2-a Warfarin in methanol was added to human liver microsomes suspended in phosphate buffer (0.1 M, pH 7.4) containing EDTA.
↵2-b The kinetic parameters were determined based on the Michaelis-Menten equation. Data are presented as mean ± S.E.