Endo T, Higashino K, Hada T, Imanishi H, Muratani K, Kochibe N, Kobata A
Department of Biochemistry, University of Tokyo, Japan.
Cancer Res. 1990 Feb 15;50(4):1079-84.
Asparagine-linked oligosaccharides were quantitatively released by hydrazinolysis from an alkaline phosphatase, Kasahara isozyme, which was purified from FL amnion cells. Almost all of the oligosaccharides (98%) were acidic components, all of which can be converted to neutral oligosaccharides upon sialidase digestion. Structural analysis of the oligosaccharides by sequential exoglycosidase digestion in combination with methylation analysis revealed that the alkaline phosphatase of FL cells contains sialylated mono-, bi-, tri-, and tetraantennary complex type sugar chains with the Gal beta 1----4GlcNAc beta 1---- outer chains. Some of the tetraantennary sugar chains contain a single Gal beta 1----4GlcNAc beta 1----3Gal beta 1----4GlcNAc beta 1---- outer chain on their Man alpha 1----6 arm. Both fucosylated and nonfucosylated trimannosyl cores were found in the sugar chains. However, it is of interest that the core portion of monoantennary oligosaccharide was not fucosylated and that of the tetraantennary oligosaccharide with a tetrasaccharide outer chain was completely fucosylated.
通过肼解从从FL羊膜细胞纯化的碱性磷酸酶（Kasahara同工酶）中定量释放出天冬酰胺连接的寡糖。几乎所有的寡糖（98%）都是酸性成分，经唾液酸酶消化后所有这些酸性成分均可转化为中性寡糖。通过顺序外切糖苷酶消化结合甲基化分析对寡糖进行结构分析表明，FL细胞的碱性磷酸酶含有唾液酸化的单天线、双天线、三天线和四天线复合型糖链，其外链为Galβ1→4GlcNAcβ1→。一些四天线糖链在其Manα1→6臂上含有一条单一的Galβ1→4GlcNAcβ1→3Galβ1→4GlcNAcβ1→外链。在糖链中发现了岩藻糖基化和非岩藻糖基化的三甘露糖核心。然而，有趣的是，单天线寡糖的核心部分未被岩藻糖基化，而具有四糖外链的四天线寡糖的核心部分则完全被岩藻糖基化。
