Glossary of PharmacologyAffinityDefinition:The extent to which a ligand binds to a receptor, and it is dictated by the ability of the ligand to form an agonist-receptor complex. It is determined by the ligand-receptor dissociation constant Kd. Affinity is inversely proportional to Kd and a high Kd value indicates a weak binding and a low affinity.Linked terms: Equilibrium dissociation constant (Kd) |