Resolution of some glycopeptides of hen ovalbumin by reverse-phase high-pressure liquid chromatography

Reverse-phase high-pressure liquid chromatography has been shown to be useful in fractionation of oligosaccharides containing N-acetyl amino sugars on the basis of stereochemical differences. Data in this paper show this same stereochemical selectivity can be obtained for glycopeptides. Using dilute aqueous phosphate for elution, three major high-mannose glycopeptides from ovalbumin can be separated on the analytical scale in a few minutes and the same method can also be used for preparation of the glycopeptides on the milligram scale. High-field proton NMR spectroscopy is used to identify two of the compounds as the mannose-5 and -6 glycopeptides (E3 and D3) and the third as the mannose-6 glycopeptide substituted by two N-acetyl glucosamine (GlcNAc) residues (C3B). The NMR spectra and analytical chromatograms of the glycopeptides show high purity and freedom from contaminants previously identified in ovalbumin glycopeptides.