Table 1

Binding properties of WT and mutant β2ARs

Construct	[³H]Dihydroalprenolol		Pindolol
Construct	K_d ± S.E.	B_max ± S.E.	K_i [S.E. interval]	Hill
	nM	pmol/mg	nM
WT	0.20 ± 0.02	14.0 ± 4.5	0.93 [0.892–0.965]	−1.08
D130N	0.22 ± 0.01	1.0 ± 0.2	0.92 [0.882–0.960]	−1.15
D130A	0.20 ± 0.02	5.8 ± 1.0	0.83 [0.813–0.851]	−1.01
CAM	0.21 ± 0.01	5.4 ± 1.0	0.75 [0.708–0.787]	−0.90

Saturation and competition binding assays were performed on membranes derived from COS-7 cells transiently expressing the WT or mutants’ receptors. Values are from three to five independent experiments performed in triplicate. The IC₅₀ values used for calculations of K _i values were obtained from means of pIC₅₀ values determined by nonlinear regression analysis and the S.E. interval from pIC₅₀ ± S.E.