FUCOIDIN .2. THE HYDROLYSIS OF A METHYLATED FUCOIDIN PREPARED FROM FUCUS-VESICULOSUS
FUCOIDIN .2. THE HYDROLYSIS OF A METHYLATED FUCOIDIN PREPARED FROM FUCUS-VESICULOSUS
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DOI：
10.1039/jr9500000827
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发表时间：
1950-01-01
期刊：
影响因子：
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通讯作者：
PERCIVAL, EGV
中科院分区：
文献类型：
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作者：
CONCHIE, J;PERCIVAL, EGV
在甲基化岩藻糖素水解物的糖部分中鉴定出L岩藻糖(约1份)、3-甲基L岩藻糖(约3份)和2：3-二甲基L岩藻糖(约1份)。本实验中所用的褐藻糖素是从1945年夏季采集的干燥、磨碎的泡囊褐藻中制备的。该产物与第一部分(J.，1950,717)中描述的岩藻糖素样品具有可比性，但没有进行密集纯化。含[a]g-118“，水解度38%的L岩藻糖，含Ca5.9，Mg0-2，Na0-9，K0-1-0-2，SO32×8y0，灰分硫酸盐占总硫酸盐的一半，在100℃下用N-氢氧化钠脱除36%的总硫酸盐需要36h。用氢氧化钠和甲基硫酸盐甲基化得到了一种[a]g-107‘，含有Ca5.1，Mg0.2，Na0.8，K0-05，SO25.9，OME15.8Y0，其中灰分中的硫酸盐占总含量的57%。因此，显然，至于卡拉胶多糖(Buchanan，Percival和Percival，J.，1943，51；Dewar和Percival，J.，1947,1622)，在甲基化过程中，与硫酸盐基团结合的金属不会被钠取代。上述产物中所有的有效羟基都被取代，这表现在用乙酸酐和吡啶处理时发生了少量的乙酰化反应。醋酸岩藻糖素的乙酰基含量为LS。O~O。如果假定基本公式为(C，H，0，S0，Ca，.5)，甲基化衍生物将含有OME 12-0y0，而乙酸酯OAc将含有15*0y0。在实践中获得的略高的值归因于少量更高取代度的“外来”多糖的存在，而不是由于在甲基化过程中被取代的岩藻糖单元中的硫酸盐基团的损失。
L-Fucose (ca. 1 part), 3-methyl L-fucose (ca. 3 parts) and 2: 3-dimethyl L-ftlcose (ca. 1 part) have been identified in the carbohydrate portion of the hydrolysate of a methylated fucoidin. A branched structure in which 1: 2-a-links predominate is suggested for the polysaccharide.THE fucoidin used in this series of experiments was prepared from dried, ground Fucus vesiculosus collected in the summer months of 1945. The product was comparable with the specimens of fucoidin described in Part I (J., 1950, 717) but the intensive purification was not applied. It had [a] g-118", gave 38% of L-fucose on hydrolysis, and contained Ca 5.9, Mg 0-2, Na 0-9, K 0-1-0-2, and SO, 32* 8y0, the sulphate of the ash accounting for half the total sulphate. It required 36 hours at 100" to remove 36% of the total sulphate with N-sodium hydroxide. Methylation with sodium hydroxide and methyl sulphate gave a product having [a] g-107'and containing Ca 5.1, Mg 0.2, Na 0.8, K 0-05, SO, 25.9, and OMe 15.8 y0, in which the sulphate in the ash comprised 57% of the total. Evidently, therefore, as for the carragheen polysaccharides (Buchanan, Percival, and Percival, J., 1943, 51; Dewar and Percival, J., 1947, 1622) the metals combined with the sulphate group were not displaced by sodium during the methylation process. That all the available hydroxyl groups were substituted in the above product was shown by the fact that on treatment with acetic anhydride and pyridine an insignificant amount of acetylation occurred. The acetyl content of fucoidin acetate was found to be lS. O~ o. If the basic formula is assumed to be (C, H, 0, S0, Ca,. 5), the methylated derivative would contain OMe 12-0y0, and the acetate OAc 15* 0y0. The slightly higher values obtained in practice are attributed to the presence of small amounts of more highly substituted" foreign" polysaccharides rather than to the loss of sulphate groups from the substituted fucose units during methylation.