脆江蓠凝集素的部分性质及细胞凝集作用

PARTIAL PROPERTIES AND CELL AGGLUTINATION OF GRACILARIA BURSA-PASTORIS LECTIN

脆江蓠藻体的磷酸盐缓冲液浸提液 ,经硫酸铵分级沉淀 ,再经DEAE -Sepharose和SephadexG 10 0层析纯化 ,得到脆江蓠凝集素 (GBL) .经测定该凝集素是一种分子量为 33.1× 10 3 ～ 33.8× 10 3 的糖蛋白 ,分子中含有 11%的中性糖 ,具有很高的耐热性 .GBL的凝血活性可被某些单糖或双糖及卵粘蛋白抑制 ,当浓度为 2 .34 μg/mL时引起兔红细胞凝集 ,浓度为 18.75 μg/mL时凝集绵羊红细胞 ,但对鸡、鸭、鸽子红细胞及人A、O、或B型血细胞没有凝集作用 .GBL能够凝集两种单细胞藻类 ,当浓度为 18.75 μg/mL时能凝集盐生杜氏藻 ,但藻细胞密度减少到 18.3× 10 4 /mL时不能发生凝集作用 ;GBL浓度为 9.37μg/mL时引起蛋白核小球藻凝集 ,但当藻细胞密度减少到 2 8.9× 10 4 /mL也不产生凝集反应 .GBL还能够凝集正常的枯草芽孢杆菌和经过热处理的酿酒酵母细胞 .图 3表 6参

The thallus of Gracilaria bursa-pastoris was extracted with PBS and then isolated by fractionation with (NH 4) 2SO 4. The purification of crude lectin was carried out by DEAE-Sepharose ion exchange, followed by Sephadex G-100 filtration. This purified lectin (GBL) is a glycoprotein with a relative molecular weight of 33 100～33 800, containing 11% neutral saccharide. Its agglutinating activity was found to be tolerant of high temperature, but inhibited by the presence of some mono- or bisaccharides and ovalbumin. GBL could agglutinate rabbit erythrocytes at 2.34 μg/mL and sheep erythrocytes at 18.75 μg/mL, respectively, but had no agglutinating activities for erythrocytes from chicken, duck, pigeon and human A, B and O blood cell groups. Furthermore, GBL agglutinated two species of unicellular algae, Dunaliella salina and Chlorella pyrenoidosa, but these agglutinations did not happen if the cell numbers of D.salina were decreased to 9.2×10 4 /mL and C. pyrenoidosa to 18.3×10 4 /mL. GBL also agglutinated natural cells of Bacillus subtilis and Saccharomyces cerevisiae treated by heating. Fig 3, Tab 6, Ref 14