Ganglioside biosynthesis in rat liver. Characterization of UDP-N-acetylgalactosamine -- GM3 acetylgalactosaminyltransferase.
Ganglioside biosynthesis in rat liver. Characterization of UDP-N-acetylgalactosamine -- GM3 acetylgalactosaminyltransferase.
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大鼠肝脏中神经节苷脂的生物合成。
DOI：
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发表时间：
1981
期刊：
影响因子：
--
通讯作者：
K. Decker
中科院分区：
文献类型：
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作者：
H. Senn;C. Cooper;P. Warnke;M. Wagner;K. Decker
在大鼠肝脏富含高尔基体的部分中研究了 UDP-N-乙酰半乳糖胺 - GM3 乙酰半乳糖胺基转移酶（GM2-合酶）。无细胞系统中的活性需要去污剂的存在；发现辛基葡萄糖苷对刺激酶最有效。 GM2-合酶的最佳活性在 pH 7.2、0.8% 辛基葡萄糖苷、10 mM Mn2+ 和 5 mM CDP-胆碱存在下获得。后者用于抵消高尔基体部分中核苷酸焦磷酸酶活性引起的快速糖核苷酸水解。 UDP-N-乙酰半乳糖胺和添加的 GM3 的表观 Km 值分别为 0.035 mM 和 0.1 mM。如果仅使用内源性GM3作为糖脂受体，会得到不同的结果。在这种情况下，UDP-N-乙酰半乳糖胺的表观Km值为0.18 mM，并且Co2+和Fe2+在激活GM2-合酶方面超过了Mn2+。在最佳测定条件下，在添加 GM3 和 5 mM CDP-胆碱的情况下，测量富集高尔基体部分的比活性为 25-30 nmol X mg Protein-1 X h-1；内源性 GM3 作为唯一的糖脂受体，V 计算为 9 nmol X mg Protein-1 X h-1。
UDP-N-acetylgalactosamine--GM3 acetylgalactosaminyltransferase (GM2-synthase) was studied in a Golgi-rich fraction from rat liver. Activity in a cell-free system required the presence of detergents; octyl glucoside was found to be the most effective in stimulating the enzyme. Optimal activity of GM2-synthase was obtained at pH 7.2, in the presence of 0.8% octyl glucoside, 10 mM Mn2+ and 5 mM CDP-choline. The latter was used to counteract the rapid sugar nucleotide hydrolysis caused by a nucleotide pyrophosphatase activity in the Golgi fraction. The apparent Km values for UDP-N-acetylgalactosamine and added GM3 were 0.035 mM and 0.1 mM, respectively. Different results were obtained if endogenous GM3 only was used as the glycolipid acceptor. In this case, the apparent Km value for UDP-N-acetylgalactosamine was 0.18 mM and Co2+ and Fe2+ exceeded Mn2+ in activating GM2-synthase. Under optimal assay conditions and in the presence of added GM3 and 5 mM CDP-choline, the specific activity of the enriched Golgi fraction was measured to be 25-30 nmol X mg protein-1 X h-1; with endogenous GM3 as the sole glycolipid acceptor, V was calculated to be 9 nmol X mg protein-1 X h-1.
大鼠肝脏中的神经节苷脂生物合成：胞苷-5-单磷酸-n-乙酰神经氨酸：苏木精（GM3）唾液酸转移酶的表征。
DOI：
10.1016/0005-2760(80)90080-6
发表时间：
1980
期刊：
Biochimica et biophysica acta
影响因子：
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作者：
Eppler,CM;Morré,DJ;Keenan,TW
通讯作者：
Keenan,TW