Table 1

Determination of the relative contribution of CYP2C19, CYP2D6, and CYP1A2 to bufuralol 1′ hydroxylation in human liver using recombinant data

rCYP	P-450 Content	ApparentK_m	V_max	CYP Content in Human Liver Microsomes	CL_int (V_max/K_m)	Abundance-AdjustedCL_int
	pmol/mg	μM	nmol/min/nmol P-450	pmol/mg	ml/min/nmol P-450	%
CYP2C19	32	36	36.9	19	1.02	5
CYP2D6	12	3.4	128	10	37.7	95
CYP1A2	39	176	4.56	45	0.03	<1

Method: Data previously generated for CYP2C19, CYP2D6, and CYP1A2 with bufuralol was recalculated on a nmol P-450 basis, and intrinsic clearances were then calculated.

2-a Rates normalized with respect to specific content of each CYP present immunochemically in human liver microsomes (Rodrigues, 1999).