Sequencing of xyloglucan oligosaccharides by partial Driselase digestion: the preparation and quantitative and qualitative analysis of two new tetrasac

The pentasaccharide (XXG), obtained from Rosa xyloglucan, was converted to two isomeric tetrasaccharides, a and b (Xyl1·Glc3), by mild acid hydrolysis. During hydrolysis in 2 M trifluoroacetic acid at 90°C, optimal yields of a and b were obtained after 20–40 min. Each tetrasaccharide was purified by preparative paper chromatography and high-pressure liquid chromatography (HPLC). The two isomers were distinguished by the products of their partial digestion with Driselase, which hydrolyses the glucosidic bonds sequentially from the non-reducing terminus: a and b yielded cellobiose and Xyl → Glc → Glc, respectively, showing that they were and , respectively. Tetrasaccharide b was chromatographically identical, upon HPLC on Dionex CarboPac PA1, with the tetrasaccharide produced from XXG by the action of Tropaeolum