Structure of a complex-type sugar chain of human glycophorin A

Abstract

Tryptic glycopeptide T1 of human glycophorin A was subjected to hydrazinolysis. After N-acetylation, the complex-type oligosaccharides were isolated by gel-filtration. The major neutral oligosaccharide (2000 MW) was purified by a combination of ion-exchange and gel-permeation chromatography. Treatments with endo- and exo-glycosidases, periodate oxidation and methylation analysis indicated that the major neutral oligosaccharide has the following structure: Gal.beta.1 .fwdarw. 4GlcNAc.beta.1 .fwdarw. 2Man.alpha.1 .fwdarw. 6(GlcNAc.beta.1 .fwdarw. 4) (Gal.beta.1 .fwdarw. 4GlcNAc.beta.1 .fwdarw. 2Man.alpha.1 .fwdarw. 3)Man.beta.1 .fwdarw. 4GlcNAc.beta.1 .fwdarw. 4(Fuc.alpha.1 .fwdarw. 6)GlcNAc. This oligosaccharide was retained by Ricinus communis agglutinin-Sepharose and retarded by Sepharose 4B coupled with erythroagglutinating E4 isolectin from Phaseolus vulgaris. Retention by concanavalin A-Sepharose was observed only after treatment of the oligosaccharide with .beta.-galactosidase.