Margolis R K, Finne J, Krusius T, Margolis R U
Arch Biochem Biophys. 1984 Feb 1;228(2):443-9. doi: 10.1016/0003-9861(84)90009-2.
Dopamine beta-hydroxylase present in the soluble matrix of bovine adrenal medullary chromaffin granules contains biantennary complex oligosaccharides and high-mannose oligosaccharides in a molar ratio of approximately 2:1. The high-mannose oligosaccharides contain an average of six mannose residues. The largest biantennary oligosaccharides (40% of the total) have two complete peripheral branches consisting of sialic acid-galactose-N-acetylglucosamine, but an equal proportion lack sialic acid on one branch and the remainder lack N-acetylglucosamine and/or galactose. Affinity chromatography on lentil lectin-agarose demonstrated that 84% of the dopamine beta-hydroxylase biantennary oligosaccharides are substituted by fucose on the core N-acetylglucosamine which is linked to asparagine. Based on carbohydrate concentration and the proportions of biantennary and high-mannose oligosaccharides, it would appear that the four dopamine beta-hydroxylase subunits of Mr congruent to 75,000 are not identical with respect to their oligosaccharide moieties. In chromaffin granule membranes, high-mannose and biantennary oligosaccharides comprise 20 and 35%, respectively, of the glycoprotein carbohydrate. Almost 40% is present in the form of large complex oligosaccharides with three or more antennas, less than 3% of which have both a core fucose residue and a 2,6-substituted alpha-linked mannose residue. Chromaffin granule membranes also contain a small proportion (approximately 6%) of O-glycosidically linked glycoprotein oligosaccharides which are predominantly monosialyl derivatives of galactosyl-N-acetylgalactosamine. The ratio of N-acetyl- to N-glycolylneuraminic acid in dopamine beta-hydroxylase and the glycoproteins of chromaffin granule membranes is approximately 1.5:1, which is within the same range as that previously found in membrane gangliosides and in the chromogranins isolated from the soluble granule matrix.
存在于牛肾上腺髓质嗜铬颗粒可溶性基质中的多巴胺β-羟化酶含有双触角复合寡糖和高甘露糖寡糖，其摩尔比约为2:1。高甘露糖寡糖平均含有六个甘露糖残基。最大的双触角寡糖（占总数的40%）有两个完整的外周分支，由唾液酸-半乳糖-N-乙酰葡糖胺组成，但相等比例的寡糖在一个分支上缺乏唾液酸，其余的则缺乏N-乙酰葡糖胺和/或半乳糖。在扁豆凝集素-琼脂糖上进行亲和层析表明，84%的多巴胺β-羟化酶双触角寡糖在与天冬酰胺相连的核心N-乙酰葡糖胺上被岩藻糖取代。根据碳水化合物浓度以及双触角和高甘露糖寡糖的比例，看来四个分子量约为75,000的多巴胺β-羟化酶亚基在其寡糖部分并不相同。在嗜铬颗粒膜中，高甘露糖和双触角寡糖分别占糖蛋白碳水化合物的20%和35%。几乎40%以具有三个或更多触角的大复合寡糖形式存在，其中不到3%同时具有核心岩藻糖残基和2,6-取代的α-连接甘露糖残基。嗜铬颗粒膜还含有一小部分（约6%）O-糖苷连接的糖蛋白寡糖，它们主要是半乳糖基-N-乙酰半乳糖胺的单唾液酸衍生物。多巴胺β-羟化酶和嗜铬颗粒膜糖蛋白中N-乙酰神经氨酸与N-糖基神经氨酸的比例约为1.5:1，这与先前在膜神经节苷脂和从可溶性颗粒基质中分离出的嗜铬粒蛋白中发现的比例范围相同。
