HPCE AS AN ANALYTICAL PROBE FOR ASSESSING IRREVERSIBLE LIGAND/MACROMOLECULE BINDING INTERACTIONS

High Performance Capillary Electrophoresis (HPCE) is rapidly becoming recognized as a valuable tool for clinical and biomedical analysis. In this paper, we present a novel application of this technique for performing ligand binding analysis for drug/protein systems. Specifically, metabolites of the antiarrhythmic procainamide have been studied with respect to their irreversible binding to hemoglobin and histone proteins. Using Hughes-Klotz analysis, free zone HPCE is shown to give comparable binding constants to FIA-EC. Further, information regarding the nature of the binding interaction is provided by analyzing the electrophoretic profiles associated with the protein complex. Advantages of this format include broad applicability to samples of limited volume and the ability to consider binding of a single ligand to several different macromolecules in a single analysis. Improvements in deleterious wall interactions may ultimately permit independent quantitation of free and bound protein as well as free and bound ligand in some systems.