Principles of Competitive Binding Assays (Saturation Analyses). I. Equilibrium Techniques

Abstract

The principles of competitive binding assays are reviewed, with emphasis on the differentiation of equilibrium vs. sequential saturation techniques. Three methods of equilibrium analysis are outlined that differ from each other in the relative concentrations of labeled ligand and binder used in the incubation system. The linearization of dose-response curves through the use of the logit plot is discussed. The importance of the knowledge of the effective affinity constant K for optimization of the assays is stressed, and two methods of estimating K are demonstrated with a digoxin-antidigoxin-antiserum system.