Graphical analysis of competitive binding of comparable concentrations of ligand, inhibitor and protein. Ligand binding to serum albumin.

Biochemical pharmacology

PubMedID: 6626238

Kragh-Hansen U. Graphical analysis of competitive binding of comparable concentrations of ligand, inhibitor and protein. Ligand binding to serum albumin. Biochem Pharmacol. 1983;32(18):2679-81.
In contrast to analysis for competitive binding in enzyme kinetics, no linear plot for analysing competitive binding of two ligands to a protein, where the concentrations of the three reactants are comparable, seems to exist. In the present communication it is shown that in this situation a linear plot can be obtained by the use of the simple equation VA/VB = KA/KB X [Af]/[Bf], where VA and VB are the average number of moles of ligand A and ligand B bound per mole of protein, respectively; [Af] and [Bf] are the concentrations of free ligand A and free ligand B, respectively; and KA and KB are the corresponding association constants. The plot is commented on both theoretically and experimentally using ligand binding to human serum albumin as an example.