| Résumé | Constitutional studies of three polysaccharides prepared from Serratia marcescens cells by a sequence of phenol extraction, ultracentrifugation, and fractionation by Cetavlon are described. Methylation of the polysaccharides followed by acid hydrolysis yielded 2,3,4,6-tetra-O-methyl-D-glucose, 2,4,6-tri-O-methyl-D-glucose, 2,4,6-tri-O-methyl-D-mannose, 4,6-di-O-methyl-D-glucose, 2,6-di-O-methyl-D-glucose, and an unidentified di-O-methyl-glucose. The acidic components found were: 2,3,4-tri-O-methyl-D-mannuronic acid, 3-O-(2,3,4-tri-O-methyl-D-mannuronosyl)-2,4,6-tri-O-methyl-D-glucose, and O-2,3,4-tri-O-methyl-D-mannuronosyl-(1 → 3)-O-2,4,6-tri-O-methyl-D-glucosyl-(1 → 3)-2,4,G-tri-O-methyl-D-glucose. The polysaccharides are composed of a main chain of D-glucose and D-mannose residues joined by 1,3-glycosidic bonds. Some glucose residues carry branches at C2 and C4 which terminate in either D-glucose or D-mannuronic acid residues. The three polysaccharides studied had similar chemical structures but varied in the amounts of component sugars and degree of branching. |
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