NOBIPOL, Department of Biotechnology, Norwegian University of Science and Technology (NTNU), Sem Saelands veg 6/8, NO-7491 Trondheim, Norway.
Carbohydr Polym. 2012 Oct 1;90(2):1092-9. doi: 10.1016/j.carbpol.2012.06.048. Epub 2012 Jun 26.
Water-soluble (1→3)-β-D-glucans with 1,6-linked branches (SBG), originally isolated from the cell walls of Saccharomyces cerevisiae and partially depolymerised for optimal performance in wound healing applications, were studied by size exclusion chromatography (SEC) with multi-angle laser light scattering (MALLS) detector and a viscosity detector at both high and ambient column temperatures. The strongly aggregating materials could be dispersed as single chains in water following partial carboxymethylation (degree of substitution (DS) 0.51 or higher). Lower DS (0.23) also dispersed as single chains provided a column temperature of 80 °C was applied. Reduction of reducing ends prior to carboxymethylation was required to avoid alkaline peeling and hence to obtain correct molecular weight distributions of the native material. DS was determined using (13)C NMR and potentiometric titration (range 0.23-0.91). Further analysis of CM-SBG in the single chain state suggested a randomly coiled behaviour with marginal influence of the branches in terms of macromolecular dimensions, which were close to those of CM-curdlan. The result of the investigation is a simple and reliable protocol for preparing undegraded and un-aggregated SBG derivatives, which are well suited as a standard analysis of the molecular weight distribution of SBG-like molecules.
从酿酒酵母细胞壁中分离出来的、具有 1,6 键合支链的水溶性（1→3）-β-D-葡聚糖（SBG），经部分解聚以优化在伤口愈合应用中的性能，采用高和环境柱温下带有多角度激光光散射（MALLS）检测器和粘度检测器的尺寸排阻色谱（SEC）进行了研究。强烈聚集的材料在经过部分羧甲基化（取代度（DS）0.51 或更高）后可以在水中分散成单链。较低的 DS（0.23）也可以在 80°C 的柱温下分散成单链。在进行羧甲基化之前需要还原还原端，以避免碱性剥皮，从而获得天然材料的正确分子量分布。DS 采用（13）C NMR 和电位滴定法（范围 0.23-0.91）测定。在单链状态下对 CM-SBG 的进一步分析表明，其具有无规卷曲行为，支链对大分子尺寸的影响较小，与 CM-环糊精的尺寸相近。该研究的结果是一种简单可靠的制备未降解和未聚集的 SBG 衍生物的方法，非常适合作为 SBG 类分子分子量分布的标准分析。
