Isolation and Characterization of Alkali-Labile Oligosaccharide Units from Porcine Erythrocyte Glycophorin1

Abstract
The oligosaccharide units of glycophorin isolated from porcine erythrocyte membranes were released by alkaline borohydride treatment and purified by gel filtration and ion-exchange chromatography. Structures of the O -glycosidic oligosaccharides were determined by methylation analysis, the methylated sugar being identified by gas-liquid chromatography-mass spectrometry and nitrous acid deamination after hydrazinolysis. The major oligosaccharide was a trisaccharide, Gal(1⇒3)[Neu-NGly(2⇒6)]GalNAc. The other oligosaccharides were larger and contained GlcNAc. One was a pentasaccharide, Gal(1⇒3)Gal(1⇒4)GlcNAc(1⇒3)Gal(1⇒3)GalNAc. The structure of the trisaccharide was also analyzed by direct-probe mass spectrometry of the permethylated derivative, and the result obtained was consistent with the proposed structure.