多天线糖链对运铁蛋白与受体结合及内吞的研究

应用系列凝集素柱层析法（伴刀豆球蛋白，小扁豆凝集素，欧曼陀罗凝集素）分别从正常人血清及孕妇血清中提纯含有二天线无核心岩藻糖复杂型糖链的运铁蛋白及含有多天线无核心岩藻糖复杂型糖链的运铁蛋白。与正常的含有二天线糖链的运铁蛋白相比，含有多天线糖链的运铁蛋白与ＳＭＭＣ－７７２１细胞膜表面的运铁蛋白受体的亲和力下降，但最大结合量不变，此外，其在内吞过程中于细胞膜上的停留时间延长。结果表明糖链结构改变对运铁蛋白的功能有影响。

Study on Receptor Binding and Endocytosis of Transferrin Carrying High Branched Oligosaccharides

Transferrin carrying biantennary complex type oligosaccharides without core-fucose and transferrin carrying high branched complex type oligosaccharides were isolated from sera of healthy individuals and pregnant women respectively, by using serial lectin-Sepharose affinity chromatography (ConA,LCA,DSA).These two kinds of transferrins were used to study their binding and endocytosis with transferrin receptors on the surface of SMMC-7721 cells.Although the maximum binding per cell was similar for the two kinds of transferrins,the high branched transferrin exhibited a much lower affinity for the transferrin receptor than the biantennary transferrin.It was also found that there was difference in the endocytosis of the two kinds of transferrin. These results suggested that the alteration of oligosaccharide structure of transferrin has effect on the function of transferrin.