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Chemical structure and chain conformation of the water‐insoluble glucan isolated from Pleurotus tuber‐regium
Author(s) -
Zhang Lina,
Zhang Mei,
Dong Jing,
Guo Ji,
Song Yinyin,
Cheung Peter Chi keung
Publication year - 2001
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/1097-0282(200111)59:6<457::aid-bip1050>3.0.co;2-i
Subject(s) - chemistry , radius of gyration , glucan , polysaccharide , intrinsic viscosity , aqueous solution , size exclusion chromatography , gel permeation chromatography , chromatography , random coil , circular dichroism , crystallography , organic chemistry , polymer , enzyme
A water‐insoluble polysaccharide (TM8) was isolated from sclerotium of Pleurotus tuber‐regium by extraction with 0.5 M NaOH aqueous solutions at 120°C. Its chemical structure was confirmed by infrared, high performance liquid chromatography, gas chromatography, and 13 C NMR in dimethylsulfoxide (DMSO) to be composed of β‐(1 → 3)‐ D ‐glucan backbone chain linked with a branched glucose, one out of every three glycosyl units being substituted at C6 position. The glucan TM8 in DMSO was fractionated by nonsolvent addition method into ten fractions, and the solution properties were studied by size exclusion chromatography combined with multiangle laser light scattering (SEC‐MALLS) and viscometry in DMSO at 30°C. The dependencies of intrinsic viscosity [η] and radius of gyration 〈 s 2 〉 z 1/2 on weight‐average molecular mass M w for this glucan were found to be [η] = (9.24 ± 0.2) × 10 −2 M w 0.51 ± 0.02 (cm 3 g −1 ) and 〈s 2 〉 z 1/2 = (3.67 ± 0.3) × 10 −2 M w 0.56 ± 0.02 (nm) in the range of M w from 1.07 × 10 4 to 77.4 × 10 4 . Based on current theories for a wormlike chain, the conformational parameters of the glucan TM8 were found to be 408 (nm −1 ) for M L , 3.1 (nm) for q , and 16.8 for C ∞ , suggesting that the polysaccharide exists as a dense random‐coil chain in DMSO, due to branched structure. © 2001 John Wiley & Sons, Inc. Biopolymers 59: 457–464, 2001