Calculating specific binding by subtracting apparent NSB from total binding of [3H]EB to α4β2 nAChR leads to errors in estimating dissociation constants and binding site concentrations. A. Apparent specific binding (dashed lines) calculated by subtracting apparent NSB (α = 0.1) from total binding is less than the true specific binding (solid lines). These errors in specific binding lead to errors in estimating Kd1 and Kd2 (B and C) and R1T and R2T (D and E) from a two sites model that includes ligand depletion but excludes NSB. B and D were obtained with α = 0.01; C and E were obtained with α = 0.1. The x-axis in B-E is an index of ligand depletion. Binding data shown or used in this figure were calculated with two sites modelfree.
Person and Wells BMC Biophysics 2011 4:19 doi:10.1186/2046-1682-4-19