文章基本信息

标题：UDP-galactose:globotriaosylceramide alpha-galactosyltransferase activity in rat pheochromocytoma (PC12h) cells.
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作者：S Pal ; M Saito ; T Ariga 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：1992
卷号：33
期号：3
页码：411-417
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：The activity of alpha-galactosyltransferase in cultured rat pheochromocytoma subcloned (PC12h) cells was examined using Gb3 as the acceptor for the galactose from UDP-galactose. The major reaction product was identified as gal alpha 1-3Gb3 based on its mobility on thin-layer chromatographic (TLC) plates and susceptibility to specific galactosidases. The enzyme activity in PC12h cells was the highest at pH 7.0 while the presence of Triton CF-54 (0.1%) and Mn2+ (5 mM) was required for its full activity. The apparent Km values for Gb3 and UDP-galactose were 57 and 17 microM, respectively. The enzyme activity in PC12h cells was compared with that in parent PC12 cells, in which gal alpha 1-3Gb3 is not expressed in an appreciable amount. In the enzyme reaction with exogenous Gb3, the enzyme activity in PC12h cells was about 1.5-fold higher than that in PC12 cells. In the absence of exogenous Gb3, this difference became even more pronounced; gal alpha 1-3Gb3 was generated from endogenous Gb3 at a much higher rate in PC12h cells than in PC12 cells. These findings suggest that the higher level of the alpha-galactosyltransferase activity in PC12h cells may, at least in part, be responsible for the accumulation of unique neutral glycosphingolipids having gal alpha 1-3 terminal residues in the cells.