In this paper,the chemical analysis and spectrum analysis methods were used for investigating the level 1 sugar chain structure of Porphyridium Cruentum polysaccharide (EPS). The results of GC analysis showed that the sugar moiety of this polymer EPS was composed of three neutral monosaccharides (xyl,glc and gal) , and molar ratio was 2.96:1.25:3.06. Infrared spectrum analysis showed that EPS was sulfurie acid ester polysaccharide,and its absolute configuration was β. The results of chemical analysis revealed that the main linkage of EPS was β-( 1→3 ) , and there were a few of 1→4 and 1→6 linkages. A large of galactoses exsited at the end or branch of sugar chain,but xylose and glucose were distributed specially close to main chain. NMR analysis displayed that sulfuric acid ester linked on C-6 ,and glycosidic bond was βconfiguration. CC-MS on-line analysis further confirmed that EPS was a heteropolysaccharide.and sugar chains structure mainly contained 1→3 linkage and small number of 1→4,1→6 linkage. Based on above comprehensive analysis,the repeat units of polysaccharide produced by P. cruentum could be inferred as D-Xyl and D-Clc, which were present at the main chain with β-(1→3,1→4) linkage and D-Gal mainly existed at the end of main chain and branched chain.%为明确紫球藻多糖的化学结构,本文采用化学分析和光谱分析方法对紫球藻多糖的一级糖链结构进行了分析.GC分析表明该多糖由木糖、葡萄糖和半乳糖组成,为一种杂多糖,其摩尔比为:2.96:1.25:3.06;红外光谱分析结果显示紫球藻多糖为硫酸化多糖,糖苷键类型为β构型；化学分析结果推断紫球藻多糖糖链连接方式以1→3为主,存在少量1→2,1→4,1→6键型,且半乳糖在支链或主链末端有较大量的存在,木糖和葡萄糖在主链或靠近主链区域有特定分布；NMR分析显示紫球藻多糖的硫酸酯基连在C-6上,且多糖的糖苷键为β型；GC-MS联机分析进一步确定紫球藻多糖为一种主要含有1→3糖苷健,并含有1→4,1→6糖苷键的杂多糖.综合上述分析,推断出紫球藻多糖的糖链主链的重复单元结构.
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