EXPERIMENTAL STUDIES IN METAL AFFINITY DISPLACEMENT CHROMATOGRAPHY OF PROTEINS

Metal affinity displacement chromatography was employed for the purification of proteins. The mobile phase modifier imidazole was shown to exhibit complex induced gradients in these displacement systems resulting in different imidazole microenvironments in each protein displacement zone. Furthermore, the induced imidazole gradient produced an elevated displacer concentration at the rear of the displacement train. While adsorption isotherms measured under the initial carrier conditions were unable to predict these displacements, isotherms measured under the induced imidazole conditions qualitatively predicted the effluent displacement profiles. It is believed that these induced imidazole gradients speed up the kinetics of the displacement process and are in part responsible for the sharp boundaries seen in these separations. This work demonstrates the ability of this bioseparation technique to effect efficient multicomponent separations and illustrates the importance of mobile phase modifier effects in metal affinity displacement chromatography.