METAL AFFINITY DISPLACEMENT CHROMATOGRAPHY OF PROTEINS

Immobilized metal ion affinity chromatographic (IMAC) systems were employed in the displacement mode for the simultaneous concentration and purification of proteins. This work demonstrates that proteins can be employed as efficient displacers of other proteins under appropriate conditions in IMAC systems and that the displacement behavior is due to the specific interactions of the proteins with the immobilized Cu2+ support. The adsorption isotherms of a variety of proteins were measured and the effect of crossing adsorption isotherms on the displacement chromatographic process was investigated. Tailing observed with certain proteins in metal affinity displacement chromatography was significantly improved by the appropriate use of imidazole as a mobile phase modifier. This hybrid bioseparation technique combines the unique selectivity of IMAC with the high throughput and purity obtained in displacement chromatography.