Structures of asparagine-linked oligosaccharides from hen egg-yolk antibody (IgY). Occurrence of unusual glucosylated oligo-mannose type oligosaccharides in a mature glycoprotein

Publisher Website
Google Scholar
Abstract
Asparagine-linked oligosaccharides present on hen egg-yolk immunoglobulin, termed IgY, were liberated from the protein by hydrazinolysis. AfterN-acetylation, the oligosaccharides were labelled with a UV-absorbing compound,p-aminobenzoic acid ethyl ester (ABEE). The ABEE-derivatized oligosaccharides were fractionated by anion exchange, normal phase and reversed phase HPLC, and their structures were determined by a combination of sugar composition analysis, methylation analysis, negative ion FAB-MS, 500 MHz1H-NMR and sequential exoglycosidase digestions. IgY contained monoglucosylated oligomannose type oligosaccharides with structures of Glcα1-3Man7–9-GlcNAc-GlcNAc, oligomannose type oligosaccharides with the size range of Man5–9GlcNAc-GlcNAc, and biantennary complex type oligosaccharides with core region structure of Manα1-6(±GlcNAcβ1-4)(Manα1-3)Manβ1-4GlcNAcβ1-4(±Fucα1-6)GlcNAc. The glucosylated oligosaccharides, Glc1Man8GlcNAc2 and Glc1Man7GlcNAc2, have not previously been reported in mature glycoproteins from any source.