麦胚凝集素对红细胞膜阴离子通透性的影响  

THE EFFECT OF WHEAT GERM AGGLUTININ ON ANION TRANSPORT IN THE ERYTHROCYTE MEMBRANES

作　　者：许红[1] 徐颖 张志鸿[1] 

机构地区：[1]复旦大学生理学和生物物理学系,上海200433

出　　处：《实验生物学报》1994年第4期477-481,共5页Acta Biologiae Experimentalis Sinica

基　　金：国家自然科学基金

摘　　要：本文研究了WGA通过红细胞骨架对Band 3主要功能——阴离子通透性的影响。采用NO_2^-测定法和NH_4Cl等渗膨胀法,发现WGA作用使膜阴离子通透性降低,并且这种作用随WGA浓度增加而愈加明显。在特定条件下,高浓度WGA会引起部分红细胞明显变形。并由此改变WGA对膜阴离子通透性效应。此外,还通过NGA对WGA作用的恢复效应及对红细胞渗透脆性的研究,进一步探讨了WGA的作用机制。The wheat germ agglutinin (WGA) has been recognized as the lectin that can agglutinate human erythrocytes. It is reported recently that the binding of WGA to the glycophorin blocks the morphological conversions of discocyte echinocyte. Glycophorin is thought to be associated with Band 3, the anion transport protein,, via the cytoskeleton proteins Band 4.1, spec-trin and ankyrin. The effect of WGA on the anion transport across the erythrocyte membranes was measured by NO2- transport and NH4 C1 isotonic swelling, two different methods developed by our laboratory in recent years. The results showed that the rate of anion transport was decreased, depending on WGA concentration, This effect became saturated when WGA concentration reached 2-3 μg/ml. We have also observed that in certain conditions when the morphological conversion of discocyte→ellipto cyte was induced by high concentration of WGA, the rate of anion transport could be reversely increased. Furthermore, the effect of WGA on erythrocyte osmotic fragility was studied. The results indicated that the osmotic fragility was reduced after adding WGA to the erythrocyte suspension, which means the erythrocyte cytoskeleton is more stable under this condition. All effects that WGA exerted above were instantly abolished by adding N-acetylglucosamine which has specific binding sites on WGA. In conclusion, the binding of WGA to the sialic acid groups of glycophorin can lead to the conformational changes in sa-charides and such changes will be transferred via glycophorin, cytoskeleton to Band 3, which causes the final change of anion transport. The effect is indirect, so the change is small (-10%). The effect is also reversible, which means that it results from the allosteric change in the cytoskeleton.

关 键 词：麦胚凝集素 红细胞 阴离子 通透性 

分 类 号：Q272[生物学—细胞生物学]