Affinity electrophoresis in agarose gels. Theory and some applications

Affinity electrophoresis is the electrophoresis of components which interact during the electrophoresis procedure. Among the numerous modifications of the basic principle, affinity electrophoresis in agarose gels combined with subsequent immunochemical detection (crossed affinity immunoelectrophoresis) has emerged as a useful means of characterizing biospecific macromolecular interactions. Demonstration of ligand-binding proteins, enumeration of binding sites, evaluation of microheterogeneous forms, and estimation of binding constants can be achieved with this procedure even when analyzing small amounts of unpurified material. With an emphasis on interactions between lectins and glycoproteins as model systems, the principles and applicability of crossed affinity immunoelectrophoresis are exemplified. This includes examples of modifications developed for screening for lectins in plant extracts, for estimation of the binding capacity of affinity matrices, and for the calculation of dissociation constants.