常山凝集素的分离纯化及其性质研究

 本文采用分子筛层析和离子交换技术,从植物常山(Dichroa febrifuga Lour)的鲜叶中,分离纯化出一种新的凝集素,定名为常山凝集素(DFL)。并对其理化性质进行了鉴定:测得其亚基分子量为37,000道尔顿;等电点为4.2。DFL是一种糖蛋白,糖含量为2.8％。DNS-CI法测得其肽链的N-末端为L-缬氨酸。本文还对其糖专一性、不同动物红细胞的凝集专一性,以及对猪精子和某些肿瘤细胞的凝集活性等生物学性质进行了研究。

PURIFICATION AND CHARACTERIZATION OF THE LECTIN FROM DICHROA FEBRIFUGA LOUR (DFL)

Dichroa febrifuga Lour is a Chinese herbal medicine widely in use. Its extract contains an active component able to agglutinate the red blood cell of rabbit. Fresh leaves of Dichroa febrifuga Lour were extracted by 0.9% NaCl/PBS mixture. The crude lectin was isolated from the extract by (NH4)2SO4 fractionation, and purified by gel filtration on Sephadex G-100 and ion exchange chromatography on DEAE-cellulose column. The product was named Lectin from Dichroa febrifuga Lour (DFL) and appeared as a single band on polyacrylamide gel electrophoresis both at alkaline and acidic pH. It is a homogeneous glycoprotein as shown by periodic acid-Schiff procedure. The molecular weight determined by SDS-polya-crylamide gel electrophoresis is 37,000 dalton. The N-terminal amino acid residue of the lectin identified by DNS-Cl method is L-valine. It is an acidic protein with pI = 4.2. The lectin is able to agglutinate the blood cells from different animals. This ability can be inhibited by D-fructose, D-sorbose and L-fucose. The DFL can also agglutinate the hog sperms and the tumor cells from Hepatoma 22, Sarcoma 180 Crocker and E. ascitic carcinoma in vitro.