Effects of ligand multivalency in binding studies: a general counterpart of the Scatchard analysis

A general counterpart of the Scatchard analysis has been developed which takes into account the valence of the ligand. Its use is first demonstrated by application to binding data obtained by exclusion chromatography of mixtures of Dextran T2000 and concanavalin A (a bivalent ligand) on a column of porous glass beads (Glyceryl-CPG 170) equilibrated at 5°C with phosphate-chloride buffer (pH 5.5), I 0.5. A recycling partition equilibrium study with Sephadex G-100 as gel phase then provides a quantitative evaluation of the interaction between haemoglobin and a monoclonal mouse antihaemoglobin antibody preparation in 0.1 M phosphate (pH 7.0) in order to emphasize the ability of the present analysis to consider collectively binding results obtained with a range of acceptor concentrations. Finally, the use of the generalized Scatchard analysis to assess acceptor site homogeneity is illustrated by reappraisal of results for the binding of glyceraldehyde-3-phosphate dehydrogenase to erythrocyte membranes.