Abstract:

Carbohydrate microarray has become a powerful tool to explore the structure-function relationship between protein-carbohydrate, but it depends on enough reducing terminal oligosaccharides with aldehyde group. Nostoc oligosaccharides are a kind of oligo(1→2)-α-D-glucopyranosyl-(1→2)-β-D-fructofuranoside. To acquire a full series of α-1,2-gluco-oligosaccharides from oligo(1→2)-α-D-glucopyranosyl-(1→2)-β-D- fructofuranoside, the terminal fructose of four Nostoc oligosaccharides were removed using acid hydrolysis methods under the condition of 0.5 mol/L trifluoroacetic acid(TFA) treated at 95 ℃ for 9 min, respectively. Following hydrolyzed products were separated and purified using high performance liquid chromatography(HPLC), and then electrospray ionization-collision-induce dissociation tandem mass spectrometry(ESI-CID-MS/MS) and matrix assisted laser desorption ionization(MALDI)-MS were used to identify the removing of terminal fructose and sequenced, α-1,2-Glc5, Glc7, Glc8 and Glc9 were acquired. The mixture of Nostoc-Octa and Nostoc-Hexa treated with 0.5 mol/L TFA at 95 ℃ for 45 min were used to acquire low degree of polymerization(DP) of α-1,2-gluco-oligosaccharides, which were separated with P2 column, ESI-MS and MALDI-MS were used to analysis these oligosaccharides, α-1,2-gluco-oligosaccharides with the degree of polymerization 2, 3, 4 and 6 were obtained. Finally, full series of α-1-2-gluco-oligosaccharides from 2 mer to 9 mer were acquired successfully.

Key words: Nostoc oligosaccharide, Fructose removing, α-1,2-Gluco-oligosaccharide, Electrospray ionization-collision-induce dissociation tandem mass spectrometry(ESI-CID-MS/MS)