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目的分离纯化归芪多糖AAP-2A,并对其结构特征进行研究。方法采用水提醇沉法提取归芪多糖(AAP),通过Sevag法脱除蛋白,DEAE-52纤维素柱色谱,葡聚糖凝胶柱色谱纯化等手段,得到1种新的归芪多糖AAP-2A。使用苯酚硫酸法测定了AAP-2A的含糖量,色谱技术检测了多糖紫外及红外性质、相对分子质量、绝对分子质量、分子构象及相对分子质量分布、单糖组成及其摩尔比值等特征。采用甲基化法和NMR法研究了AAP-2A的连接方式、主链和支链结构及分支点特征。结果 AAP-2A总糖量为98.98%,且不含核酸及蛋白质,红外吸收光谱分析表明AAP-2A有明显的多糖特征吸收,AAP-2A的相对分子质量大于6.68×105,绝对分子质量为2.252×106,由鼠李糖、半乳糖、阿拉伯糖、葡萄糖组成,其物质的量比依次为1∶2.13∶3.22∶6.18。主链骨架由1,3-α-L-鼠李糖,1,3-β-D-半乳糖,1,3、1,5、1,3,5-α-L-阿拉伯糖和1,4、1,4,6-α-D-葡萄糖组成,侧链分支点位于阿拉伯糖的3位和葡萄糖的4位,侧链分支由1位连接的α-D-葡萄糖组成。结论AAP-2A为一种新的中性归芪杂多糖,其构象呈高度支化状。
OBJECTIVE To isolate and purify AAP-2A from Gui polysaccharide, and to study its structural characteristics. Methods AAP was extracted by aqueous extraction and alcohol precipitation, and the protein was removed by Sevag method, purified by DEAE-52 cellulose column chromatography and purified by Sephadex column. -2A. The sugar content of AAP-2A was determined by phenol-sulfuric acid method. The properties of UV-A and IR, molecular weight, absolute molecular mass, molecular conformation, relative molecular mass distribution, monosaccharide composition and molar ratio of polysaccharide were detected by chromatography. Methylation and NMR methods were used to study the attachment, backbone and branching structure and branching characteristics of AAP-2A. Results The total sugar content of AAP-2A was 98.98%, and no nucleic acid and protein were detected. The results of IR showed that AAP-2A had obvious polysaccharide absorption, the relative molecular mass of AAP-2A was larger than 6.68 × 105 and the absolute molecular mass was 2.252 × 106, which is composed of rhamnose, galactose, arabinose and glucose. The ratio of the substances is 1: 2.13: 3.22: 6.18. The backbone consists of 1,3-α-L-rhamnose, 1,3-β-D-galactose, 1,3,1,5,1,3,5-α-L-arabinose and 1, 4,1,4,6-α-D-glucose. The branching point of the side chain is located at position 3 of arabinose and position 4 of glucose, and the side chain branch consists of α-D-glucose connected with position 1. Conclusion AAP-2A is a new type of neutral guiqi polysaccharide with a highly branched conformation.