Flexible chain conformation of (1 → 3)-β-d

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• 作者：Xiaoyu Chen ; Xiaojuan Xu ; Lina Zhang ; John F. Kennedy
• 关键词：Poria cocos ; Flexible chain ; Conformation ; NaOH/urea aqueous solution
• 刊名：Carbohydrate Polymers
• 出版年：2009
• 出版时间：24 February 2009
• 年：2009
• 卷：75
• 期：4
• 页码：586-591
• 全文大小：583 K

文摘

A water-insoluble polysaccharide (PCS3-II) extracted from sclerotium of Poria cocos was identified as a linear (1 → 3)-β-d-glucan by ¹³C NMR and gas chromatography. Aqueous 0.5 M NaOH/0.2 M urea was a good solvent for PCS3-II and the dependence of intrinsic viscosity ([η]) on weight-average molecular weight (M_w) was established in the M_w range from 7.68 × 10⁴ to 5.14 × 10⁵ to be [η] = 3.39 × 10⁻² at 25 °C by using laser light scattering and viscometry. The chain conformation parameters of PCS3-II in the 0.5 M NaOH/0.2 M urea solution was 2.3 (± 0.3) nm for persistence length (q), 580 g mol⁻¹ nm⁻¹ for molar mass per unit contour length (M_L), 0.8 (± 0.2) nm for the diameter of the chain (d) and 3.63 for limited characteristic ratio (C_∞). The results revealed, for the first time, that PCS3-II existed as a flexible chain in 0.5 M NaOH/0.2 M urea aqueous solution.