title: Selective cleavage of glycosidic linkages: studies with the O-specific polysaccharide from Shigella dysenteriae type 3.
abstract: Treatment of the O-specific polysaccharide from Shigella dysenteriae Type 3 with hydrazine in the presence of hydrazine sulphate resulted in quantitative N-deacetylation with the formation of a modified polysaccharide containing free amino groups.  Oxidation of the modified polysaccharide with periodate did not destroy the 2-amino-2-deoxygalactose residues, thus indicating that they were substituted at position 3.  Acid hydrolysis of the modified polysaccharide afforded 3-O-(2-amino-2-deoxy-beta-D-galactopyranosyl)-D-galactose, which was identified as the N-acetyl derivative.  Deamination of the modified polysaccharide with nitrous acid cleaved the 2-amino-2-deoxy-D-galactopyranosyl linkages to give a pentasaccharide as the major product, which appeared to be the modified chemical repeating unit of the O-specific polysaccharide.
mesh_terms: D000107:Acetylation; D000942:Antigens, Bacterial / Q000032:analysis*; D003641:Deamination; D006868:Hydrolysis; D008745:Methylation; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D011135:Polysaccharides, Bacterial / Q000032:analysis; D012762:Shigella dysenteriae / Q000032:analysis*
chemical_list: D000942:Antigens, Bacterial; D011135:Polysaccharides, Bacterial