Structural studies on a polysaccharide from an edible mushroom, Termitomyces eurhizus

A polysaccharide (PS), isolated from the hot aqueous extract of the mushroo m, Termitomyces eurhizus, is found to contain, D-glucose, D-galactose, D-ma nnose and D-galacturonic acid in a mole ratio of about 0.9:0.9:1.0:09. From the periodate oxidation and methylation analysis of the PS, the linkages a mong the constituent sugar residues are identified as, D-Galp (1,6 linked), D-Manp (1,2,3 linked), D-Glcp (1,3 linked) and D-galacturonic acid. The an omeric configuration of the constituent sugar residues are determined by th e chromium trioxide oxidation studies of the acetylated polysaccharide. It is concluded that galactose and mannose have the beta-configuration while g lucose and galacturonic acid have the alpha-configuration. Based on the abo ve observations, the structure of the repeating unit of the polysaccharide was assigned as, [GRAPHICS]