Polysaccharide Scleroglucan Research Articles

Triple Helix and Random Coil of Scleroglucan in Dilute Solution

Eleven sonicated samples of a polysaccharide scleroglucan (chemically identical with but different in biological origin from schizophyllan) in 0.01N sodium hydroxide (NaOH) and dimethylsulfoxide (DMSO) at 25°C were studied by light scattering, viscometry, and ultracentrifu-gation. Data for the radius of gyration 〈S2〉1/2, the intrinsic viscosity [η], and the sedimentation coefficient s0 as functions of weight-average molecular weight Mw, combined with those for the ratio Mw (0.01N NaOH)/Mw (DMSO), showed that scleroglucan dissolves in DMSO as a single randomly coiled chain very similarly to that of schizophyllan in the same solvent, while it dissolves in 0.01N NaOH as a rodlike trimer or higher aggregates, depending on whether Mw (DMSO) is lower or higher than 2×105. From ‹S2›, [η], and s0 for samples with Mw (DMSO)≲1×105 in 0.01N NaOH, the contour length per main chain residue and the diameter of the scleroglucan trimer rod were found to be 0.30±0.03 and 2.6±0.5 nm, respectively, which agree with the reported pitch (per residue) and diameter of the schizophyllan triple helix. Thus, it was concluded that the scleroglucan trimer has essentially the same triple helical structure as that of the schizophyllan trimer. Evidence was obtained showing that the higher aggregates in 0.01N NaOH consist of trimers as building units.

Solution properties of a new polyelectrolyte derived from the polysaccharide scleroglucan

Selective, quantitative oxidation of pendant 1,6-β-linked glucopyranose residues along scleroglucan chains has yielded a new carboxylated polyelectrolyte. Study of the aqueous solution properties of the latter (named sclerox-I) has disclosed rather anomalous behaviour. Viscosity, calorimetric and chiro-optical measurements show that the interaction of sclerox-I with Ca 2+ ions leads to a change in conformation of the polyanions, probably of the type random coils → ordered, elongated forms.

Anti-hypercholesterolemic action of scleroglucan and pectin in chickens.

SummaryPectin and the polysaccharide scleroglucan reduced dietary hypercholestero-lemia in chicks; this reduction was accompanied by an increased excretion of chloroform-methanol extractable lipid, including cholesterol. The chemical dissimilarity of pectin and scleroglucan suggests that the anti-hyper-cholesterolemic activity of the two materials may be due to their physical rather than to their chemical properties.