龙须菜(Gracilaria lemaneiformis)多糖的分离纯化及其组成研究

PURIFICATION AND COMPOSITION OF POLYSACCHARIDE FROM GRACILARIA LEMANEIFORMIS

以龙须菜粗多糖为原料,利用离子交换层析分离纯化,紫外光谱、醋酸纤维薄膜电泳和凝胶过滤层析法鉴定多糖的纯度及其分子量,同时进一步采用气相色谱分析龙须菜多糖的单糖组成。结果表明,利用蒸馏水、0.3mol/L NaCl和1.2mol/L NaCl溶液分步洗脱,DEAE-Sephadex A-25离子交换层析纯化得到龙须菜多糖的三个组分G1、G2和G3,得率分别为3.61%、69.26%、18.70%;G1、G2和G3均显示为单一电泳谱带和单一洗脱峰,无蛋白、核酸杂质,分子量依次为21993、48460、61031U;G2和G3的单糖组成主要为半乳糖、3.6-内醚半乳糖及少量葡萄糖;G2糖链通过1→2键与1→6键方式连接,存在非还原末端基及连三羟基,G3糖链则通过1→3键与1→2键方式连接。

The polysaccharides from marine algae Gracilaria lemaneiformis were purified, and the containing monosaccharide composition was studied. The crude polysaccharide was loaded on a DEAE-Sephadex A-25 column and eluted with H20, 0.3mol/L NaC1 and 1.2mol/L NaCl in turn. Three polysaccharides marked G1, G2 and G3 were separated with the yield of 3.61%, 69.26% and 18.70%, respectively. G1, G2, and G3 components showed single polysaccharide component on ultraviolet （UV） spectrum, cellulose acetate membrane electrophoresis, and gel filtration chromatography. UV spectra measurements confirmed that the three polysaccharide components have no protein and nucleic acid. Their purity was up to be single electrophoresis band and single elution peak. The average molecular weight of G1, G2, and G3 were 21993, 48460, and 61031 U, respectively. The monosaccharide component in G2 and G3 were identified as mainly galactose and 3,6-anhydrogalactose. The sugar-chain of G2 is composed of 1→2 bond, 1→6 bond and includes non-reducing end group and three hydroxies, while G3 is composed of 1→3 bond and 1→2 bond.