STRUCTURE OF A WATER-SOLUBLE POLYSACCHARIDE FROM THE SEEDS OF CASSIA-ANGUSTIFOLIA
STRUCTURE OF A WATER-SOLUBLE POLYSACCHARIDE FROM THE SEEDS OF CASSIA-ANGUSTIFOLIA
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DOI：
10.1055/s-2007-969161
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发表时间：
1986-08-01
期刊：
影响因子：
2.7
通讯作者：
GUPTA, PC
中科院分区：
文献类型：
--
作者：
ALAM, N;GUPTA, PC
从决明子中分离出一种由d -半乳糖和d -甘露糖摩尔比为3:2组成的水溶性半乳甘露聚糖。甲基化多糖的水解裂变产生三种甲基化糖：(a) 2,3-二- o -甲基-d -甘露糖，(b) 2,3,4-三- o -甲基-d -半乳糖，(c) 2,3,4,6-四- o -甲基-d -半乳糖，摩尔比为2:1:2。多糖的部分酸水解得到五种低聚糖：(a)外二糖，(b)半乳糖生物甘露糖，(c)甘露糖，(d)甘露糖，(e)半乳糖二糖。高碘酸氧化为59.7%，甲基化为60%。硼氢化钠对高碘酸盐氧化多糖的还原和随后的水解表明（1 .fwdarw）的存在。4)和(1)。6)糖苷键。因此，半乳甘露聚糖的主链被发现是由（1 . 2）w组成的。4)-连接的甘露吡喃基单位含有。-糖苷，成键，而（1 .）6)有关.alpha。-葡萄糖苷键合的半乳糖酰基单位形成分支点。
A water-soluble galactomannan consisting of D-galactose and D-mannose in the molar ratio 3:2 has been isolated from the seeds of Cassia angustifolia. Hydrolytic fission of the methylated polysaccharide resulted in three methylated sugars: (a) 2,3-di-O-methyl-D-mannose, (b) 2,3,4-tri-O-methyl-D-galactose, and (c) 2,3,4,6-tetra-O-methyl-D-galactose in the molar ratio 2:1:2. Partial acid hydrolysis of the polysaccharide afforded five oligosaccharides: (a) epimelibiose, (b) galactobiosylmannose, (c) mannobiose, (d) mannotriose, and (e) galactobiose. Periodate oxidation of the polysaccharide indicated 59.7% end group while methylation gave 60%. Sodium borohydride reduction of the periodate oxidised polysaccharide and subsequent hydrolysis revealed the presence of (1 .fwdarw. 4) and (1 .fwdarw. 6)-glycosidic bonds. Thus, the main chain of the galactomannan was found to consist of (1 .fwdarw. 4)-linked mannopyranosyl units having .beta.-glycosidic, bonds while (1 .fwdarw. 6)-linked .alpha.-glucosidically bonded galactopyranosyl units form the branching points.