Interaction between immobilized and soluble protein subunits. Analysis and applications

A distinctive property of oligomeric and self-associating proteins is the high specificity of the subunit recognition process. Protein subunits immobilized covalently on a solid matrix maintain this characteristic and are able to bind soluble subunits of the same or a closely related protein under conditions that allow the establishment of a finite association/dissociation equilibrium. The basic theory for studying the immobilized-soluble subunit interaction is presented together with the methodology for a proper protein immobilization. Specific examples are discussed to illustrate on the one hand benefits and caveats of using immobilized protein subunits to measure interaction constants, and on the other preparative applications of subunit affinity columns.