TABLE 4.

B_max and affinity for S-CIT on SERT WT and mutants

Experiments performed on membrane preparations from COS7 cells transiently expressing SERT WT or indicated mutants. The K_d and B_max values of S-CIT binding were calculated from nonlinear regression analysis of [³H]S-CIT binding in the presence increasing concentrations of unlabeled S-CIT using 11 consecutive concentrations performed in triplicate. The IC₅₀ values used in the estimation of K_d values were calculated from means of pIC₅₀ values and the S.E. interval from the pIC₅₀ ± S.E. ND, not detectable.

SERT construct	S-CIT
	Bmax	Kd	N
	fmol/100 μl of membrane	nm
WT	468 ± 32	2.8 (2.5; 3.3)	3
R104D	139 ± 24	4.8 (3.2; 7.2)	3
D493R	ND	ND	3
R104D/D493R	152 ± 10	4.5 (3.5; 5.6)	3