PURIFICATION OF RECOMBINANT PROTEIN-A BY AQUEOUS 2-PHASE EXTRACTION INTEGRATED WITH AFFINITY PRECIPITATION

Aqueous two-phase extraction incorporated affinity precipitation was examined as a technique for protein purification. An enteric coating polymer, Eudragit S100, was employed as a ligand carrier. Eudragit was specifically partitioned to the top phase in the aqueous two-phase systems. For application of this method to purification of recombinant protein A using human IgG coupled to Eudragit in an aqueous two-phase system, 80% of protein A added was recovered with 81% purity. The purity was enhanced 26-fold by this method. The IgG-Eudragit could be used repeatedly for the purification process. This separation method should be applicable to industrial-scale purification as a new purification procedure combining the advantages and compensating for the disadvantages of the aqueous two-phase method and affinity precipitation method.