TABLE 1

Kinetic constants of PMAT substrates Values are given as means ± S.D. with n = 3.

Substrate	K_m	V_max	V_max/K_m
	μM	pmol/min/mg protein	μl/min/mg protein
MPP⁺	33 ± 7^a	2800 ± 116^a	85
Serotonin	114 ± 12^a	6524 ± 197^a	57
Dopamine	329 ± 8^a	18,222 ± 168^a	55
Tyramine	283 ± 23	5055 ± 147	18
Histamine	10,471 ± 2550	99,610 ± 17,299	10
Norepinephrine	2606 ± 258^a	20,561 ± 902^a	8
Epinephrine	15,323 ± 3947^a	38,442 ± 7705^a	3
TEA	6593 ± 1702	5827 ± 918	1