TABLE I.

Decay Times of Transient Currents Blocked by L-Glutamate, L-Aspartate, D-Aspartate, and Succinate in D444 Mutant Transporters

	L-Glutamate	L-Aspartate	D-Aspartate	Succinate	TBOA
D444C	17.7 ± 1	19.3 ± 1	18.4 ± 1	15.7 ± 1.1	4.8 ± 0.3
D444C after MTSES	ND	10.2 ± 0.4	ND	8.7 ± 1.5	ND
D444E	ND	10.6 ± 1	ND	5.1 ± 0.7	5.6 ± 1.2
D444S	11.0 ± 1.2	12.2 ± 0.6	12.8 ± 0.6	9.9 ± 0.7	6 ± 0.6

Decay times of transients suppressed by 10 μM of d,l-TBOA (160 μM in the case of D444S) or by 10 mM of the other compounds (except for succinate in the case of D444E, where the concentration of succinate was 15 mM) are given in ms and are the mean ± SEM of 3–10 oocytes. In the case of D444S and D444C, the decay time was determined at −100 mV and with D444E at +80 mV.