Lehle L, Bauer F, Tanner W
Arch Microbiol. 1977 Jul 26;114(1):77-81. doi: 10.1007/BF00429634.
Membranes of Saccharomyces cerevisiae were separated on urografin gradients. The specific activity of the light membranes (endoplasmic reticulum), the Golgi-like vesicles and the plasma membrane in transferring mannosyl residues from GDP-mannose to mannoproteins and to dolichyl monophosphate has been determined. The first mannose of the O-glycosidically linked manno-oligosaccharides is incorporated with the highest specific activity by the endoplasmic reticulum. The incorporation of the second to fourth mannosyl groups is catalysed with increasing activity also by the Golgi-like vesicles and the plasma membrane. The incorporation of mannosyl groups into weak alkali-stable positions (N-glycosidically linked chains) is carried out with almost the same specific activity by all three membrane fractions, however, dolichol-dependent and -independent steps could not be distinguished as yet. The results are discussed in terms of a sequential addition of sugar residues along the route of export of the mannoprotiens. The dolichol-dependent steps seem to occur on the endoplasmic reticulum and thus very early in the event.
酿酒酵母的膜在泛影葡胺梯度上进行分离。已测定了轻膜（内质网）、类高尔基体囊泡和质膜在将甘露糖基残基从GDP-甘露糖转移至甘露糖蛋白和二磷酸多萜醇时的比活性。O-糖苷键连接的甘露寡糖的第一个甘露糖由内质网以最高的比活性掺入。第二至第四个甘露糖基的掺入也由类高尔基体囊泡和质膜以逐渐增加的活性催化。所有三个膜组分将甘露糖基掺入弱碱稳定位置（N-糖苷键连接的链）时的比活性几乎相同，然而，多萜醇依赖性和非依赖性步骤目前尚无法区分。根据甘露糖蛋白输出途径中糖残基的顺序添加来讨论结果。多萜醇依赖性步骤似乎发生在内质网上，因此在该过程中非常早的时候就发生了。
