Ligand binding assays at equilibrium: validation and interpretation

The focus of this review paper is factors affecting data interpretation in ligand binding assays under equilibrium conditions. Protocols for determining K d (the equilibrium dissociation constant) and K dA (the equilibrium inhibitor constant) for receptor ligands are discussed. The basic theory describing the interaction of a radiotracer and an unlabelled competitor ligand with a receptor is developed. Inappropriate experimental design may result in ligand depletion and non‐attainment of equilibrium, distorting the calculation of K d and K dA . Strategies, both theoretical and practical, will be given to avoid and correct such errors, thus leading to the determination of reliable values for these constants. In…

• MR
  Medical Research Council