Application of cationic latex particles for protein separation

We have prepared cationic latex particles with amino groups on their surface. The particles were composed of a polystyrene core and a poly(glycidyl methacrylate) surface layer, to which hexamethylenediamine was immobilized by means of coupling with epoxy groups. The zeta potential of the particles was approximately 30 mV and the isoelectric point was 10.5. The latex particles preferentially adsorbed acidic proteins through an electrostatic interaction. We compared the capacity and selectivity in adsorption of acidic proteins on the cationic particles and on diethylaminoethyl (DEAE)-Sepharose gel, which has been conventionally used. The latex particles were twenty times more efficient in adsorption of proteins than DEAE-Sepharose gel. Acidic proteins encoded by the adenovirus Ela gene were selectively separated from crude cell extracts using the cationic latex particles.