TABLE 1

Kinetic parameters of denopamine glucuronidation in microsomes obtained from humans and experimental animals, and recombinant UGT2B7

Denopamine was incubated with microsomes and UDP-glucuronic acid for 30 min (10 min in the case of rat and rabbit liver microsomes). The kinetic parameters were calculated with GraphPad Prism software. Each value represents best-fit values ± S.E. of triplicate points.

Source of UGT	K_m			V_max			V_max/K_m
Source of UGT		G1	G2	G1	G2	G1	G2
	mM			nmol/min/mg protein			μl/min/mg protein
Rat liver^a	0.0022 ± 0.0003		2.68 ± 0.07		1220
Rabbit liver^a	0.018 ± 0.003		2.77 ± 0.12		152
Dog liver^b	10.18 ± 0.61	3.51 ± 0.14	21.83 ± 0.99	5.68 ± 0.13	2.14	1.62
Monkey liver^b	3.91 ± 0.13	1.84 ± 0.07	7.65 ± 0.15	6.25 ± 0.11	1.96	3.40
Human liver^b		2.87 ± 0.17		7.29 ± 0.23		2.54
Human jejunum^b		2.99 ± 0.30		1.17 ± 0.06		0.39
UGT2B7^b		1.48 ± 0.05		3.58 ± 0.06		2.43

↵ a The denopamine concentration ranged from 0.78 to 200 μM, and microsomal protein was 0.1 mg/ml.
↵ b The denopamine concentration ranged from 15.6 to 4000 μM, and microsomal protein was 0.5 mg/ml.