榆耳水溶性多糖的结构特征

Stucture aspects of water soluable polysaccharide isolated from Gloeostereum Incarnatum

用3%三氯醋酸从榆耳子实体中提取出水溶性粗多糖,经乙醇分级、SepharoseCL6B纯化得到单一组分GIA.SepharoseCL6B柱层析测得GIA的相对分子质量为1 26×105.GC分析表明GIA由Man和Glc两种单糖构成,其物质的量比为1 42∶1.多糖GIA经部分酸水解、高碘酸氧化、Smith降解和甲基化分析其结构主要为β(1→3)Man和β(1→3)Glc,且在6～0处构成分枝结构,平均每11个己糖残基有2个分枝,多糖GIA的支链部分由(1→4)Glc构成,末端残基为Man,Glc.

The water soluble crude polysaccharide had been exacted by 3% CCl_3COOH from Gloeostereum Incarnatum.After ethanol precipitation,Sepharose CL-6B gel filitration,the fraction of GIA was obtained.GC analysis indicate that GIA is composed of Man and Glc,The molar ratio is 1.42∶1.Its average molecular weight was estimated to be 1.26×10~5 by Seharose CL-6B gel filtation.After the methods of partial hydrolsys with acid,periodate oxidation,Smith degradation, methylation and GC-MS analysis,the results indicate that GIA is a kind of lowly branched structure.The main chain is mainly made up of β-(1→3)Man and β-(1→3)Glc,and substituted at 6~0.On average,there are two branches among 11 main chain residues.The side chain is composed of (1→4)Glc,the nonreduced end is composed of Man and Glc.