Protein displacement in dye–ligand chromatography using neutral and charged polymers

Displacement chromatography was demonstrated to perform separations efficiently under mass‐overloaded conditions, offering advantages such as increased product recovery and purity, superior resolving power, and concentration and purification in a single processing step. The use of water‐soluble polymers for protein displacement in dye–ligand chromatography was initiated in our laboratory. The polymers for displacement were selected using difference spectroscopy to monitor their interactions with a dye–ligand in solution. Non‐charged polymers such as poly(N‐vinyl pyrrolidone) and poly(N‐vinyl caprolactam) efficiently displaced lactate dehydrogenase from porcine muscle from a Blue Sepahrose column. The latter polymer, being thermosensitive, could be easily removed from the eluate and recovered by precipitation at 45 °C and low‐speed centrifugation. The positively charged polymer poly(ethylene imine) proved to be an even more efficient displacer. The dye–ligand column could be regenerated after application of displacer either by washing with a solution of the soluble ligand Cibacron Blue (in the case of non‐charged polymers) or by washing with highly alkaline solutions containing polyanions (in the case of poly(ethylene imine)) The latter formed a soluble complex with poly(ethylene imine) and stripped the column from the polymer. Copyright © 1998 John Wiley & Sons, Ltd.