刺参糖胺聚糖的亚分级和各级分的理化特征与抗凝性质

刺参糖胺聚糖及其解聚物在水溶液中可通过逐步提高所加入的醋酸钾浓度引起的沉淀作用进行亚分级。本文对有关级分的理化特征、抗凝活性及诱导血小板聚集的副作用进行了比较。原聚糖平均分子量为50000,所得各级分的分子量分别为55000,48000,41000,23000和9000,它们在不连续琼脂糖凝胶电泳中显示不同特点。化学分析表明,除两个分子量较低级分中葡糖醛酸和岩藻糖含量略低外,各級分组成糖基和硫酸酯基的分子比值与原聚糖相近似。其红外、核磁谱与原聚糖一致。各级分体外抗凝活性随分子量变小而程度不同地减弱,其中分子量对聚糖延长凝血酶时间的影响较其对部分凝血活酶时间的影响为著。分子量最小的级分无明显诱导人血小板聚集副作用。

Holothurian Glycosaminoglycan Subfractions:Their Preparation,Physico-chemical Characteristics and Anticoagulant Properties

Holothurian glycosaminoglycan(HG)subfractions were obtained via stepwise precipitation from aqueous solution of the glycan or its depolymerized derivative by increasing concentration of potassium acetate added. Five fractions showed different mean molecular weights: 55 000,48 000,41 000,23 000 and 9 000 respectively by contrast to 50 000 of the initial HG, and variations of their migration behaviour in discontinuous agarose gel electrophoresis were observed. However, their chemical composition, except for slightly less glucuronic acid and fucose contents in two fractions with lower molecular weights, and characteristics of IR as well as NMR spectra were identical with those of the original HG.Anticoagulant tests in vitro indicated that the abilities to prolong thrombim clotting time(TCT) and activated partial thromboplastin time (APTT) decreased in order of decreasing molecular weight. The prolongation of TCT caused by various fractions appeared relatively more susceptible to molecular weight than that of APTT. Only the fraction with minimum mean molecular weight possessed no significant inducibility of platelet aggregation.