SAMPLE DISPLACEMENT MODE CHROMATOGRAPHY - PURIFICATION OF PROTEINS BY USE OF A HIGH-PERFORMANCE ANION-EXCHANGE COLUMN

In sample displacement mode (SDM) chromatography, the column is overloaded with sample until it is saturated with the product of interest, while weakly binding impurities are displaced. Because the method makes use of the full capacity of a column, it is interesting for large-scale fine purfication of proteins. By using two columns in series, the product can be separated from both strongly and weakly binding impurities. The working principle of SDM was proved by using Mono Q ion-exchange columns. Crude samples of ovalbumin and soybean trypsin inhibitor were applied to one- and two-column systems and the sequence and purity of both the displaced and the eluted components were determined by off-line analysis. Conditions such as column dimensions, load flow-rate, buffer type and temperature have to be optimized for each target protein and associated impurities in order to maximize the yield and purity by minimizing overlapping.