STRUCTURE OF SUCCINOGLUCAN, AN EXOCELLULAR ACIDIC POLYSACCHARIDE OF ALCALIGENES FAECALIS VAR MYXOGENES

Succinoglucan, a succinylated polysaccharide ([μ]D25 -15°, water) produced by Alcaligenes faecalis var. myxogenes 10C3, consists of D-glucose, D-galactose, and succinic acid, in the approximate molar ratio of 7:1:1.5. The polysaccharide moiety was shown by methylation and periodate oxidation to consist of β-1→3-, 1→4-, and 1→6-linked glucose residues, and a small proportion of β-1→3-linked galactose residues. Removal of succinyl residues by alkali treatment furnished a desuccinylated polysaccharide ([μ]D25 -26°, water), which was oxidized by periodate at essentially the same rate as the native polysaccharide, and consumed 0.65 mole of periodate/sugar residue with production of 0.16 mole of formic acid. On acid hydrolysis the methyl derivative derived from the desuccinylated polysaccharide yielded 2,3,4,6-tetra-, 2,3,4-tri-, 2,3,6-tri-, 2,4,6-tri-, and 2,3-di-O-methyl-D-glucose and 2,4,6-tri-O-methyl-D-galactose (1:1.5:4:5:1:2 molar ratio). Periodate oxidation of the polysaccharide, followed by borohydride reduction and mild hydrolysis with acid yielded O-β-D-galactosylerythritol, O-β-D-glucosylerythritol, O-β-laminaribiosylerythritol, and O-β-laminaribiosylglycerol, together with small amounts of erythritol and glycerol. The significance of these findings in relation to the structure of the polysaccharide is discussed. © 1969, American Chemical Society. All rights reserved.