26] Chromatography of proteins on ion-exchange adsorbents

Abstract

Publisher Summary This chapter outlines general considerations which govern the use of ion-exchange chromatographic experiments emphasizing the precautions necessitated by the use of commercial adsorbents. Adsorption of proteins to ion-exchange celluloses involves primarily the formation of multiple ionic bonds among charged groups on the protein and available groups of opposite charge on the adsorbent. Chromatographic separation then depends on the differential elution of the adsorbed proteins by a variety of techniques based either upon alteration of the charge state of the protein (pH), or upon the use of agents capable of “competing” with the adsorbed protein for the charged sites on the adsorbent. The ion-exchange Sephadexes and microgranular cellulosic adsorbents have the useful property of settling from suspension quite rapidly and forming compact and rather stable sediments. This property can be exploited for large-scale batch operations, making these adsorbents useful for many crude operations for which their resistance to flow when packed into columns would seem to render them unsuitable.