TABLE 2

Estimation of the contribution ratio of RKIP and hCE2 involved in the formation of the thiolactone metabolite from prasugrel in human small intestinal S9 by the enzymatic kinetic parameters

The contents of RKIP and hCE2 in individual human small intestinal S9 (n = 4) were determined using recombinant RKIP and PNGase F-treated hCE2 by Western blotting method. The contribution ratio of RKIP and hCE2 involved in the hydrolysis reaction of prasugrel in human small intestinal S9 was estimated by using the obtained contents data and enzyme kinetic parameters.

	V_max/K_m	Individual Human Small Intestinal S9	Enzyme Contents	CL_int	Contribution Ratio (%)
	μl/min/μg protein		ng/human small intestinal S9 μg)	μl/min/μg enzyme contents
RKIP	283	HIS-063-S3	14.9	4217	52.7	42.9	9.82
		HIS-067-S3	12.8	3622	29.4
		HIS-084-S3	15.6	4415	43.4
		HIS-111-S3	7.48	2117	46.2
hCE2	1101	HIS-063-S3	3.44	3787	47.3	57.1	9.82
		HIS-067-S3	7.91	8709	70.6
		HIS-084-S3	5.24	5769	56.6
		HIS-111-S3	2.24	2466	53.8