Abstract: Partitioning of binding energy among the constituent subsites in a ligand-antibody complex can be useful in assessment of bimolecular processes in the combining site. Binding affinities of five anti-fluorescyl monoclonal antibodies for fluorescein (1) and two compounds representing its component parts, xanthenone (2) and benzoate, were studied by the fluorescence quenching technique. Dissociation constants were found to be in the ...