用β-琼胶酶和NMR光谱法研究多管藻多糖的寡糖结构

STUDIES ON THE STRUCTURE OF OLIGOMERS FROM THE POLYSACCHARIDE OF POLYSIPHONIA URCEOLATA (RHODOPHYTA) USING β－AGARASE AND NMR SPECTROSCOPY

于1990年3月用β－琼胶酶对多管藻的冷水提取多糖进行酶解，酶解液通过DEAE－SephadexA25和Bio－GelP6色谱柱分离，分离出2个带电荷的寡糖A—Ⅰ和A—Ⅱ．经1H－NMR和13C－NMR光谱法分析，确定结构式分别为61，22－二－O－甲基－63－硫酸基－新琼四糖和61，22－二－O－甲基－63，63－二硫酸基－新琼六糖，证明它们构成多管藻多糖分子的单位组分。

The polysaccharide extracted by cold water from PolyslPhonta urceolata collected on March 1990, in Qingdao, was hydrolyzed using β－agarase fromPseudomonas atlantica. The mixture after hydrolysis was precipitated by adding 95%ethanol solution, tYren the uPper clear solution was evaporated in vacuo. this ethanolconeentrate of enzyndc hydrolyzate was chromatographed on DEAE-Sephadex A25and then Bio-Gel P6 columns. Two charged agarooligomers A-|Ⅰ and A -Ⅱ were iso-lated from the eluents. Their degrees of polymerization were estimated by 1H-NMRspectra to be 2 and 3, respectively. Two oligomers gave clear resonance signals at3.41ppm and 3.52ppm in 1H-NMR, which showed the presence of methyl groups onC2 of L-galactose and C6 of D-galactose, respectivcly. A strong signa at 4.18ppm indicated that a sulfate group links with C6 of D-galactose. The structure of theoligomers A-Ⅰ and A-Ⅱ was deduced by the assignment of chendcal shifts in 1H-and 13C-NMR spectra to be 61, 22-di -nethyl -meooprotetraose -63 -sulfate and61, 22-di -methyl -neoagarohexaose - 63, 65 -disulfate, respectively, which constitutethe unit component of the polysaccharide of Polysiphonia urceolata.