Polymer displacement/shielding in protein chromatography

An overview of different applications of polymer interactions with ion-exch ange and dye-affinity chromatographic matrices is presented here. The stren gth of interaction between the ligand and the polymer plays a crucial role in deciding the mode of chromatographic application. Charged, non-ionic and thermosensitive polymers such as poly(ethylene imine), poly(N-vinyl pyrrol idone) and poly(vinyl caprolactam) respectively, show different degrees of interaction with the dye molecules in dye ligand chromatography. Polymers, with their ability of multipoint and hence strong attachment to the chromat ographic matrices, were used as efficient displacers in displacement chroma tography. The polymer displacement resulted in better recoveries and sharpe r elution profiles than traditional salt elutions. The globule-coil transit ion of the thermosensitive reversible soluble-insoluble polymer, poly(vinyl caprolactam), can be exploited in dye-affinity columns for the temperature induced displacement of the bound protein. In another situation, prior to the column chromatography of crude protein extract, polymers formed complex es with the dye matrix and "shielded" the column. The polymer shielding dec reased the nonspecific interactions without affecting the specific interact ions of the target protein to the dye matrix. (C) 2000 Elsevier Science B.V . All rights reserved.