Structural characterization of a water-soluble β-d-glucan from fruiting bodies of Agaricus blazei Murr

A β-d-glucan, Ab2-2N, was isolated from the hot-water extract of fruiting bodies of Agaricus blazei Murr by ethanol precipitation, anion-exchange and gel-permeation chromatography. Its structure was investigated by composition analysis, methylation analysis, Smith degradation, mild hydrolysis, and NMR spectroscopy. It contains a (1→6)-linked β-d-glucopyranosyl backbone, with one side chain consisting of terminal and 3-substituted β-d-glucopyranosyl residues attached at O-3 for every three backbone residues.