Marriott M, Tanner W
J Bacteriol. 1979 Aug;139(2):566-72. doi: 10.1128/jb.139.2.566-572.1979.
Membranes from Saccharomyces cerevisiae protoplasts were fractionated on a continuous sucrose gradient. Six bands were obtained, which contained altogether about 15% of the total cell protein. From their densitites, their behavior in the presence and absence of Mg2+ ions, and the distribution of marker enzymes, it was possible to identify fractions enriched in rough and smooth endoplasmic reticulum and in mitochondria. All glycosyl transfer reactions investigated where dolichyl phosphates served as glycosyl acceptors or where dolichyl phosphate- and pyrophosphate-activated sugars served as glycosyl donors showed the highest specific activity and up to 75% of the total activity in the endoplasmic reticulum. This was the case for the reactions involved in the formation of O-glycosidic as well as N-glycosidic linkages in yeast glycoprotein biosynthesis. Membrane fractions enriched in plasmalemma contained less than 3% of the corresponding activities.
将酿酒酵母原生质体的膜在连续蔗糖梯度上进行分级分离。得到了六条带,它们总共约占细胞总蛋白的15%。根据它们的密度、在有无Mg2+离子存在时的行为以及标记酶的分布,有可能鉴定出富含粗面和滑面内质网以及线粒体的组分。所有以多萜醇磷酸酯作为糖基受体或多萜醇磷酸酯和焦磷酸激活的糖作为糖基供体的糖基转移反应,在内质网中显示出最高的比活性和高达总活性的75%。在酵母糖蛋白生物合成中形成O-糖苷键和N-糖苷键所涉及的反应就是这种情况。富含质膜的膜组分所含相应活性不到3%。