Structures of the asparagine-linked sugar chain of glucose transporter from human erythrocytes.
Structures of the asparagine-linked sugar chain of glucose transporter from human erythrocytes.
复制标题
人红细胞葡萄糖转运蛋白天冬酰胺连接糖链的结构。
作者：
T. Endo;M. Kasahara;A. Kobata
人红细胞中葡萄糖转运体的天冬酰胺连接糖链通过肼水解从多肽主链中定量释放为低聚糖。它们经n-乙酰化后经NaB3H4还原转化为放射性低聚糖，经唾液酸酶处理后经阴离子交换柱层析和Bio-Gel P-4柱层析分离。通过外糖苷酶和内糖苷酶的酶切和甲基化分析，对每个低聚糖进行结构研究表明，该糖蛋白含有一个高甘露糖型低聚糖，Man9.GlcNAc。GlcNAc，以及以Man α 1----6(+/- GlcNAc β 1----4)(Man α 1----3) Man β β 1----4GlcNAc β 1----4(+/- Fuc α 1----6)GlcNAc为核心的双天线络合物型低聚糖，外链为约16个n -乙酰乳胺基单位组成的聚n -乙酰乳胺。葡萄糖转运体糖部分的这些结构特征与人红细胞的两种主要固有糖蛋白糖蛋白A和带3有很大的不同。
The asparagine-linked sugar chain of glucose transporter from human erythrocytes was quantitatively released as oligosaccharides from the polypeptide backbone by hydrazinolysis. They were converted to radioactive oligosaccharides by NaB3H4 reduction after N-acetylation and fractionated by anion-exchange column chromatography and Bio-Gel P-4 column chromatography after sialidase treatment. Structural study of each oligosaccharide by exo- and endoglycosidase digestion and methylation analysis indicated that the glycoprotein contains a high-mannose-type oligosaccharide, Man9.GlcNAc.GlcNAc, and biantennary complex-type oligosaccharides with Man alpha 1----6(+/- GlcNAc beta 1----4)(Man alpha 1----3) Man beta beta 1----4GlcNAc beta 1----4(+/- Fuc alpha 1----6)GlcNAc as their cores and the poly-N-acetyllactosamine composed of about 16 N-acetyllactosaminyl units as their outer chains. These structural features of the sugar moiety of glucose transporter are quite different from those of two major intrinsic glycoproteins of human erythrocytes, glycophorin A and band 3.