Chromatofocusing of sialoglycoproteins.

Sialoglycoproteins of different sialic acid contents have been separated from each other by chromatofocusing on the ion exchanger PBE 94 using gradients of pH 4.00 down to pH 1.00. The technique is much faster than isoelectric focusing, apparently does not result in desialylation of the sialoglycoproteins and can handle with ease 10 ng to 50 mg quantities of protein on a 22 X 0.9 cm column. The technique revealed that commercial preparations of fetuin and human acid glycoprotein contained several components. Glycophorin, desialylated by controlled neuraminidase treatment, was fractionated by chromatofocusing into several components which differed in sialic acid content and in ability to inhibit haemagglutination by wheat germ agglutinin and encephalomyocarditis and influenza viruses.