Synthesis and structural analysis of five novel oligosaccharides prepared by glucosyltransfer from β-d-glucose 1-phosphate to isokestose and nystose using Thermoanaerobacter brockii kojibiose phosphorylase Original Research Article

Five novel oligosaccharides (tetra-, penta- and hexa-saccharides) were synthesized by glucosyltransfer from β-d-glucose 1-phosphate to isokestose (O-β-d-fructofuranosyl-(2→1)-O-β-d-fructofuranosyl-(2→1)-α-d-glucopyranoside) or nystose (O-β-d-fructofuranosyl-(2→1)-O-β-d-fructofuranosyl-(2→1)-O-β-d-fructofuranosyl-(2→1)-α-d-glucopyranoside) using Thermoanaerobacter brockii kojibiose phosphorylase. The oligosaccharides were identified as 2(2-α-d-glucopyranosyl)misokestose; [O-α-d-glucopyranosyl-(1→2)]m-O-[β-d-fructofuranosyl-(2→1)]2-α-d-glucopyranoside: m=1, 2, and 3, and 2(2-α-d-glucopyranosyl)nnystose; [O-α-d-glucopyranosyl-(1→2)]n-O-[β-d-fructofuranosyl-(2→1)]3-α-d-glucopyranoside: n=1 and 2 using gas liquid chromatography analysis of the methyl derivatives, and MALDI-TOF-MS and NMR measurements of the newly formed oligosaccharides. 1H, 13C NMR signals of each saccharide were assigned using 2D-NMR techniques, including COSY, HSQC, HSQC–TOCSY, HMBC, CH2-selected E-HSQC, and CH2-selected E-HSQC–TOCSY.