Composition and biogenesis of complex carbohydrates of ox adrenal chromaffin granules
Composition and biogenesis of complex carbohydrates of ox adrenal chromaffin granules
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牛肾上腺嗜铬颗粒复合碳水化合物的组成和生物合成
DOI：
10.1016/0306-4522(77)90023-9
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发表时间：
1977
期刊：
影响因子：
3.3
通讯作者：
H. Winkler
中科院分区：
文献类型：
--
作者：
D. Geißler;A. Martinek;R. U. Margolis;R. Margolis;J. Skrivanek;R. Ledeen;P. König;H. Winkler
牛肾上腺嗜铬颗粒的复杂碳水化合物组成已经确定，因为此类分析数据是研究这些碳水化合物的生物发生和了解它们在细胞器中的功能作用的先决条件。膜糖蛋白中的主要糖是甘露糖、半乳糖和N-乙酰氨基葡萄糖，而半乳糖、N-乙酰半乳糖胺和唾液酸以高浓度存在于可溶性糖蛋白中。这些糖蛋白中的大部分半乳糖胺不存在于短“粘蛋白型”寡糖中。嗜铬粒蛋白A是一种糖蛋白，主要含有半乳糖、N-乙酰半乳糖胺和唾液酸。另一方面，可溶性多巴胺β-羟化酶具有高浓度的岩藻糖、甘露糖和N-乙酰氨基葡萄糖。这种碳水化合物组成与其他人描述的总酶的组成相似，这表明可溶性酶和膜结合酶具有相同的碳水化合物部分。唯一检测到的糖胺聚糖（粘多糖）是硫酸软骨素和硫酸乙酰肝素。糖胺聚糖在可溶物和嗜铬颗粒膜中的浓度相似；然而，膜中硫酸乙酰肝素的相对比例是可溶性区室中的两倍多。嗜铬颗粒膜还含有相对较高浓度的神经节苷脂，其中90%以上是苏铁苷。使用[3H]岩藻糖在灌注牛肾上腺中研究了糖蛋白生物合成。选择该前体是因为它提供了用其相对高浓度的糖优先标记多巴胺β-羟化酶的可能性。新形成的嗜铬颗粒的可溶性糖蛋白掺入了大量的岩藻糖放射性（其中大部分明显进入多巴胺β-羟化酶），而膜上几乎没有标记。这些结果表明多巴胺β-羟化酶的可溶性形式和膜结合形式具有不同的合成速率，并结合嗜铬颗粒的膜在多个分泌周期中重复使用的概念进行了讨论。
The complex carbohydrate composition of ox adrenal chromaffin granules has been determined, since such analytical data are a prerequisite for studies on the biogenesis of these carbohydrates and for an understanding of their functional role in the organelle. The predominant sugars in the glycoproteins of the membrane are mannose, galactose andN-acetylglucosamine, whereas galactose,N-acetylgalactosamine and sialic acid are present in high concentration in the glycoproteins of the soluble content. Most of the galactosamine in these glycoproteins is not present in short ‘mucin type’ oligosaccharides. Chromogranin A is a glycpprotein containing mainly galactose,N-acetylgalactosamine and sialic acid. On the other hand, soluble dopamine β-hydroxylase possesses a high concentration of fucose, mannose andN-acetylglucosamine. This carbohydrate composition is similar to that of the total enzyme described by others, which indicates that the soluble and membrane-bound enzyme have identical carbohydrate moieties. The only glycosaminoglycans (mucopolysaccharides) detected were chondroitin sulphate and heparan sulphate. Glycosaminoglycans are present in a similar concentration in the soluble content and in the membranes of chromaffin granules; however, the relative proportion of heparan sulphate in the membranes is over twice that found in the soluble compartment. Chromaffin granule membranes also contain a relatively high concentration of gangliosides, of which over 90% is hematoside.Glycoprotein biosynthesis was studied in perfused bovine adrenal glands using [3H]fucose. This precursor was chosen since it offered the possibility to label preferentially the enzyme dopamine β-hydroxylase with its relatively high concentration of this sugar. The soluble glycoproteins of newly formed chromaffin granules incorporated significant amounts of fucose radioactivity (most of it apparently into dopamine β-hydroxylase), whereas very little labelling of the membranes occurred. These results, which indicate that the soluble and membrane-bound forms of dopamine β-hydroxylase have different synthesis rates, are discussed in connection with the concept that membranes of chromaffin granules are reused for several secretory cycles.