Polysaccharides in fungi. II. Structural analysis of acidic heteroglycans from Tremella fuciformis berk.

Abstract

The acidic heteroglycans (AC and BC) have been isolated from the fruit bodies of Tremella fuciformis BERK, which grow in China. The structures of the AC- and BC polysaccharides containing D-xylose, D-mannose, D-glucuronic acid and O-acetyl groups were investigated by Smith degradation and methylation analysis. These results indicated that AC and BC were composed of α-1→3 linked D-mannopyranose backbone having highly branched points. D-Glucopyranosyluronic acid end groups, D-xylopyranose end groups and β-1→2 or β-1→3 linked D-xylopyranose side chains were linked to the position 2 of the mannopyranose main chain. Also, the results of Smith degradation suggest that O-acetyl groups are probably located at the glucuronic acid residues. The results indicated that the structures of the polysaccharides, AC and BC, are essentially similar. However, significant difference between AC and BC has been observed in that the ratio of the xylose residues as end groups directly linked to the mannose backbone to the xylose side chains in BC is somewhat higher than that in AC, and the proportion of glucopyranose residues as end groups in BC is slightly larger than that in AC.