Preparation and structural determination of large oligosaccharides derived from acharan sulfate

The structures of a series of large oligosaccharides derived from acharan sulfate were characterized. Acharan sulfate is an unusual glycosaminoglycan isolated from the giant African snail, Achatina fulica. Oligosaccharides from decasaccharide to hexadecasaccharide were enzymatically prepared using heparin lyase II and purified. Capillary electrophoresis and gel electrophoresis confirmed the purity of these oligosaccharides. Their structures, determined by ESI-MS and NMR, were consistent with the major repeating sequence in acharan sulfate, →4)-α-d-GlcN_pAc-(1→4)-α-l-IdoA_p2S-(1→, terminated by 4-linked α-d-GlcN_pAc residue at the reducing end and by 4,5-unsaturated pyranosyluronic acid 2-sulfate at the non-reducing end.