A 1H NMR spectroscopic approach to the unambiguous determination of glycosyl linkage positions in oligosaccharides.

A sensitive (< 1 mg) and nondestructive method was devised for the unambiguous determination of the glycosyl linkage positions in oligosaccharides using 1H NMR spectroscopy. The technique is based on the absence of a hydroxyl group on the carbon atom that participates in the glycosidic linkage. The "missing" hydroxyl group is identified by recording 1H NMR spectra of the oligosaccharide in H2O and D2O. The method is illustrated by determining the glycosyl linkage positions of maltose, Glc alpha 1-4Glc, and a branched mannopentaose, Man alpha 1-6(Man alpha 1-3)Man alpha 1-6(Man alpha 1-3)Man.