文章基本信息

标题：The citrate cleavage pathway and lipogenesis in rat adipose tissue: replenishment of oxaloacetate
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作者：F. J. Ballard ; Richard W. Hanson
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：1967
卷号：8
期号：2
页码：73-79
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：Fatty acid synthesis via the citrate cleavage pathway requires the continual replenishment of oxaloacetate within the mitochondria, probably by carboxylation of pyruvate. Malic enzyme, although present in adipose tissue, is completely localized in the cytoplasm and has insufficient activity to support lipogenesis. Pyruvate carboxylase was found to be active in both the mitochondria and cytoplasm of epididymal adipose tissue cells; it was dependent on both ATP and biotin. Alterations in dietary conditions induced no significant changes in mitochondrial pyruvate carboxylase activity, but the soluble activity was depressed in fat-fed animals. The possible importance of the soluble activity in lipogenesis lies in its participation in a soluble malate transhydrogenation cycle with NAD malate dehydrogenase and malic enzyme, whereby a continual supply of NADPH is produced. Consequently, the pyruvate carboxylase in adipose tissue both generates mitochondrial oxaloacetate for the citrate cleavage pathway and supplies soluble NADPH for the conversion of acetyl-CoA to fatty acid.
关键词：pyruvate carboxylase ; adipose tissue ; rat ; intracellular distribution ; dietary changes ; oxaloacetate formation ; lipogenesis