Arnold D, Hommel E, Risse H J
Mol Cell Biochem. 1976 Feb 16;10(2):81-95. doi: 10.1007/BF01742202.
The cell surface of embryonic chick liver cells contains transferases for mannose, fucose, galactose, N-acetyl-glucosamine and N-acetyl-neuraminic acid. Liver cells obtained by trypsin-dissociation of the tissue use the corresponding exogenous sugar nucleotides as substrates. The activities of the enzymes tested do not depend neither no the dissociation procedure nor on de novo protein synthesis. They vary considerably during development of the embryos, reaching maximal values at the 8th+/-1 day and at the 12th+/-1 day. Glycoproteins are the final stable endogenous acceptors for all sugars. Mannose transfer proceeds via a two or multistep reaction sequence. In a first step labile lipophilic intermediates are formed. Mannose can be liberated by treating the intermediates with 0.1 N HCl at 100 degrees C. In a second reaction step mannose becomes attached to glycoproteins. From embryonic chick liver cells a glycopeptide fraction has been obtained by pronase digestion followed by several purification steps. The purified glycopeptides inhibit all transferase systems and act as exogenous acceptors for mannose transfered from exogenous GDP-mannose.
胚胎鸡肝细胞的细胞表面含有甘露糖、岩藻糖、半乳糖、N-乙酰葡糖胺和N-乙酰神经氨酸的转移酶。通过胰蛋白酶消化组织获得的肝细胞利用相应的外源性糖核苷酸作为底物。所检测酶的活性既不依赖于解离过程，也不依赖于从头蛋白质合成。它们在胚胎发育过程中变化很大，在第8±1天和第12±1天达到最大值。糖蛋白是所有糖类的最终稳定内源性受体。甘露糖转移通过两步或多步反应序列进行。第一步形成不稳定的亲脂性中间体。在100℃用0.1N盐酸处理中间体可释放出甘露糖。在第二步反应中，甘露糖与糖蛋白结合。通过链霉蛋白酶消化，随后经过几个纯化步骤，从胚胎鸡肝细胞中获得了一个糖肽组分。纯化的糖肽抑制所有转移酶系统，并作为从外源性GDP-甘露糖转移来的甘露糖的外源性受体。
