TABLE 1

Kinetic parameters of transporter mutants in the absence or presence of CuPh

V_max and K_m values were calculated for each mutant in the absence or presence of CuPh. V_max is shown as a percentage of EAAT1 or CL-EAAT1 without CuPh treatment. Mutants in the upper part of the table are in the background of EAAT1 (800 μM CuPh); those in the lower part of the table are in the background of CL-EAAT1 (15 μM CuPh). Values are expressed as mean ± S.E. for at least three independent repeated experiments.

Mutant	Control		CuPh
Mutant	V_max	K_m	V_max	K_m
	%	μM	%	μM
Background of EAAT1
EAAT1	100	28.7 ± 3.5	92.6 ± 5.2	30.6 ± 2.8
A243C/S366C	36.2 ± 4.8	39.2 ± 6.3	20.1 ± 2.2^*	42.3 ± 3.8
A243C	80.2 ± 4.2	37.2 ± 4.4	81.3 ± 3.6	39.8 ± 3.5
S366C	40.3 ± 5.1	36.3 ± 4.2	45.1 ± 3.9	38.5 ± 2.6
Background of CL-EAAT1
CL-EAAT1	100	30.6 ± 1.2	93.2 ± 2.9	28.4 ± 3.3
A243C/I453C	82.7 ± 1.9	26.0 ± 1.4	52.7 ± 3.6**	52.6 ± 8.4^*
A243C/T456C	62.6 ± 1.1	35.9 ± 3.4	35.7 ± 4.5**	45.1 ± 2.1
A243C	86.7 ± 3.2	35.8 ± 3.5	87.5 ± 2.4	40.1 ± 4.7
I453C	55.2 ± 4.7	31.4 ± 4.4	57.4 ± 3.4	32.3 ± 4.1
T456C	38.9 ± 3.6	29.5 ± 4.1	38.2 ± 4.3	30.3 ± 3.9

↵* P < 0.05; **P < 0.01 vs. control (no treatment with CuPh) using Student's t test.