文章基本信息

标题：CMP-NeuAc:Gal beta 1-->4GlcNAc alpha 2-->6sialyltransferase catalyzes NeuAc transfer to glycolipids.
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作者：M Nakamura ; A Tsunoda ; K Yanagisawa 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：1997
卷号：38
期号：9
页码：1795-1806
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：Using mammalian gene-overexpression system, in vitro catalytic activities of CMP-NeuAc:Gal beta 1-->4GlcNAc alpha 2-->6sialytransferase on glycosphinogolipid acceptors were analyzed. We transfected the mammalian expression vector containing the cDNA that was cloned from Daudi cells into COS-1 cells, and selected monoclonal transfectants in the presence of G418. Although the transfected alpha 2-->6sialytransferase can catalyze NeuAc transfer onto glycoprotein acceptors more than glycolipids based on kinetic analyses, the substantial synthesis of IV6NeuAc-nLcOse4Cer was observed and the activities were 7- to 9-times higher in the transfected cells than in the mock transfectants. In addition, the transfected COS-1 cells with alpha 2-->6sialytransferase cDNA were revealed to contain a higher amount of ganglioside that has the terminal NeuAc alpha 2-->6Gal sequence in the in situ situation than the mock transfectants. These results using transfectants, together with those using the purified enzyme protein, suggest that the alpha 2-->6sialytransferase enzyme from Daudi cells can also catalyze NeuAc transfer in alpha 2-->6 linkage onto glycosphingolipid acceptors.