Chemical Structure and Molecular Weights of α-(1→3)-D-Glucan from Lentinus edodes

概要

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α-Glucan (L-FV-II) and β-glucan (L-FV-I) were isolated from fruiting bodies of Lentinus edodes by extraction with 5% NaOH/0.05% NaBH_4,then precipitation with 1M acetic acid. The analysis results of Smith degradation, high-performance liquid chromatography (HPLC), infrared spectra (IR), ^13C NMR spectra, and optical rotation indicated that L-FV-II is α-(1→3)-D-glucan with slight (1→6) branch linkages, and L-FV-I is β-(1→3)-D-glucan containing 10% protein, and with branches. The weightaverage molecular weight, M_W, number-average molecular weight, M_n, radii of gyration, <S^2>^1/2,and second virial coefficients, A_2,of L-FV-II in aqueous 0.5 M urea/0.5 M NaOH (obtained from diluting its solution in 1.0 M urea/1.0 M NaOH) and 0.25 M LiCl in dimethylsulfoxide (DMSO/0.25 M LiCl) were measured by light scattering, membrane osmometry, and size exclusion chromatography (SEC). The values of M_W and M_n for L-FV-II in 0.5 M urea/0.5 M NaOH are 24.1×10^4 and 10.9×10^4,respectively, similar to those in DMSO/0.25 M LiCl. It was proved that strong intermolecular hydrogen bonds exist in L-FV-II, resulting in its water-insolubility, but there are not any aggregates or multiple-helix structure for L-FV-II in DMSO/0.25 M LiCl. The chain of α-(1→3)-D-glucan is more extended in DMSO/0.25 M LiCl than that in the aqueous solution.
社団法人日本農芸化学会の論文
1999-07-23