SELECTIVITY IN CAPILLARY ELECTROPHORESIS - THE USE OF PROTEINS

Proteins, by their very diverse nature, provide a wide variety of opti ons for generating selectivity in capillary electrophoresis (CE). Thei r use in different modes of CE will be considered in this review. Prot eins added in solution to the background electrolyte allow separations to be made in a similar fashion to other electrokinetic chromatograph y methods, e.g., micellar separations. Alternatively, different immobi lization schemes can be used to secure proteins within the capillary; these have included capillary electrochromatography with the protein g rafted onto a silica support, or immobilization of the protein within a gel structure. Compounds varying in size from small inorganic ions t o biopolymers may be bound by proteins. There is the potential for any sort of intermolecular interaction to play a role in the binding proc ess (e.g., hydrophobic interactions, electrostatic interactions, etc.) . Very specific high-affinity binding often occurs, but also there is often weaker, non-selective binding. Frequently the interactions of ch iral compounds with proteins are stereoselective. Obtaining chiral sel ectivity has been one of the main applications of protein selectors in CE, and this use will be emphasized here in a discussion structured b y type of protein. As well as utilizing the selectivity of proteins to develop separations, the role of CE in investigating ligand-protein i nteractions will be emphasized. (C) 1997 Elsevier Science B.V.