Structural analysis of six novel oligosaccharides synthesized by glucosyl transfer from β- d-glucose 1-phosphate to raffinose and stachyose using Thermoanaerobacter brockii kojibiose phosphorylase

Abstract

Novel oligosaccharides (one tetra-, two penta-, two hexa- and one hepta-saccharides) were synthesized by glucosyl transfer from β- d-glucose 1-phosphate (β- d-G1P) to raffinose or stachyose using Thermoanaerobacter brockii kojibiose phosphorylase. Gas liquid chromatography analysis of methyl derivatives, MALDI-TOF-MS and NMR measurements were used for structural confirmation. The 1H and 13C NMR signals of each saccharide were assigned using 2D-NMR including COSY, HSQC, HSQC-TOCSY, HMBC and CH 2-selected E-HSQC techniques. These oligosaccharides were identified as 2-α- d-glucopyranosyl-raffinose, 2 G(2-α- d-glucopyranosyl) 2-raffinose, 2 G(2-α- d-glucopyranosyl) 3-raffinose, 2-α- d-glucopyranosyl-stachyose, 2 G(2-α- d-glucopyranosyl) 2-stachyose and 2 G(2-α- d-glucopyranosyl) 3-stachyose.