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标题：Trans-vaccenate is Δ13-desaturated by FADS3 in rodents
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作者：Vincent Rioux ; Frédérique Pédrono ; Hélène Blanchard 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：2013
卷号：54
期号：12
页码：3438-3452
DOI：10.1194/jlr.M042572
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：Fatty acid desaturases play critical roles in regulating the biosynthesis of unsaturated fatty acids in all biological kingdoms. As opposed to plants, mammals are so far characterized by the absence of desaturases introducing additional double bonds at the methyl-end site of fatty acids. However, the function of the mammalian fatty acid desaturase 3 (FADS3) gene remains unknown. This gene is located within the FADS cluster and presents a high nucleotide sequence homology with FADS1 (Δ5-desaturase) and FADS2 (Δ6-desaturase). Here, we show that rat FADS3 displays no common Δ5-, Δ6- or Δ9-desaturase activity but is able to catalyze the unexpected Δ13-desaturation of trans -vaccenate. Although there is no standard for complete conclusive identification, structural characterization strongly suggests that the Δ11,13-conjugated linoleic acid (CLA) produced by FADS3 from trans -vaccenate is the trans 11, cis 13-CLA isomer. In rat hepatocytes, knockdown of FADS3 expression specifically reduces trans -vaccenate Δ13-desaturation. Evidence is presented that FADS3 is the first “methyl-end” fatty acid desaturase functionally characterized in mammals.
关键词：fatty acid desaturase ; FADS cluster ; desaturase activity ; trans- vaccenic acid ; conjugated linoleic acid ; trans 11, cis 13-octadecadienoic acid ; rumenic acid