木葡聚糖纯化鉴定研究

Purification and identification of xyloglucan

中文关键词:  木葡聚糖  葡萄甘露聚糖  木聚糖  半纤维素  植物细胞壁  糖连接甲基化分析

英文关键词:Xyloglucan  glucomannan  xylan  hemicellulose  plant cell wall  methylation analysis for sugar linkage

中文摘要:

      目的 木葡聚糖(XG)是豆类、蔬菜及水果重要的半纤维素成分, 本文探讨其纯化鉴定方法。方法 从乙烯催熟猕猴桃果肉提取半纤维素II(HC?II), 采用碘沉淀, 接着阴离子交换层析。结果 将XG含量从HC-II干粉中50摩尔%提高到纯化干粉中62摩尔%。纯化的XG中葡萄糖(Glc)︰木糖(Xyl)︰半乳糖(Gal)︰岩藻糖(Fuc)比例是10︰6.9︰2.1︰0.3。凝胶过滤层析表明, 纯化的XG平均分子量是161 kDa, 而聚合物总糖的平均分子量是95 kDa。结论 糖连接分析证实了猕猴桃XG缺乏岩藻糖(Fuc), 有少量的阿拉伯木聚糖、低分子量的葡萄甘露聚糖与XG密切结合。

英文摘要:

      Objective To study the purification and identification of fruit xyloglucan (XG). Methods The cell wall XG in pericarp tissues of a ripe kiwifruit (Actinidia deliciosa) was purified from hemicellulose II extracted with 24% (w/v) KOH plus 0.02% NaBH4 using iodine precipitation and anion-exchange chromatography. Results The cell walls in the ripe kiwifruit fruits still contain a high proportion of XG. Monosaccharide analysis of purified XG showed a molar ratio of Glc︰Xyl︰Gal︰Fuc of 10︰6.90︰2.05︰0.27. Gel permeation chromatography indicated that purified XG had an average molecular-mass of 161 kDa, a value that exceeds the 95 kDa determined for total polymeric sugars. Conclusion Sugar linkage analysis confirmed the lack of fucose in kiwifruit XG, but a small amount of arabinoxylan and low Mr glucomannan remained associated with this fraction.