黑皮扁豆凝集素提纯及部分性质研究

摘要

A mannose-binding lectin (DPL) was isolated from seeds of Dolichos Purpureus L.var.by NaCl extract,ammonium sulfate precipitation,and two steps of ion-exchange chromatography.DPL showed only a single band in native-PAGE.Under reducing and non-reducing conditions,it showed two bands on SDSPAGE corresponding to molecular weight of 36.8 kD and 39.8 kD respectively.The molecular weight of the native lectin was 155 kD estimated on Sephacryl S-300 with FPLC.Our results suggest that it consists of two a unites and twoβunites without disulphide bridges.The purified DPL is a glycoprotein with 1.6% (w/w)of carbohydrates.Some physicochemical properties of DPL including heat stability and pH stability were assayed.The results indicated that it was similar to the reported mannose/glucose-specific legume lectins.%采用NaCl抽提、硫酸铵分部沉淀和2步离子交换法从黑皮扁豆中纯化得到一种甘露糖专一凝集素(DPL).在非变性电泳中纯化的DPL只有一条蛋白带,在还原及非还原条件下的SDSPAGE中呈现两条蛋白带,其分子量分别为36.8 kD和39.8 kD;利用FPLC经Sephacry1 S-300凝胶过滤测得其表观分子量为155kD,表明DPL由2个α亚基和2个β亚基组成,无二硫键.DPL的等电点为pH 6.18,含1.6%糖,为酸性糖蛋白.DPL的热稳定性和pH稳定性,与已报道的甘露糖/萄糖专一的豆科凝集素相似.