Fatty acid and lipoic acid biosynthesis in higher plant mitochondria
Fatty acid and lipoic acid biosynthesis in higher plant mitochondria
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DOI：
10.1074/jbc.275.7.5016
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发表时间：
2000-02-18
影响因子：
4.8
通讯作者：
Bourguignon, J
中科院分区：
文献类型：
--
作者：
Gueguen, V;Macherel, D;Bourguignon, J
研究了植物线粒体中脂肪酸和硫辛酸的生物合成。虽然线粒体缺乏乙酰辅酶a羧化酶，但我们的实验表明，它们含有将丙二酸盐转化为脂肪酸合成的两个主要构建单元所必需的酶设备：丙二醇和乙酰酰基载体蛋白（ACP）。我们通过一种基于高效液相色谱和质谱互补使用的新方法证明，可溶性线粒体脂肪酸合成酶主要产生以下三种主要的酰基ACP：辛烷基(C8)-、十六烷基(C16)-和十八烷基(C18)- acp。辛酸盐的生产是主要的兴趣，因为它早已被假定为硫辛酸的前体。通过使用重组H载脂蛋白突变体作为新合成的硫辛酸的潜在受体，我们能够在丙二酸、几种硫供体和辅助因子存在的情况下检测到有限数量的脂酰化H蛋白。最后，我们提出了一种方案，概述了植物线粒体中脂肪酸和硫辛酸合成的新生化途径。
Fatty acid and lipoic acid biosynthesis were investigated in plant mitochondria. Although the mitochondria lack acetyl-CoA carboxylase, our experiments reveal that they contain the enzymatic equipment necessary to transform malonate into the two main building units for fatty acid synthesis: malonyl- and acetyl-acyl carrier protein (ACP), We demonstrated, by a new method based on a complementary use of high performance liquid chromatography and mass spectrometry, that the soluble mitochondrial fatty-acid synthase produces mainly three predominant acyl-ACPs as follows: octanoyl(C8)-, hexadecanoyl(C16)-, and octadecanoyl (C18)-ACP. Octanoate production is of primary interest since it has been postulated long ago to be a precursor of lipoic acid. By using a recombinant H apoprotein mutant as a potential acceptor for newly synthesized lipoic acid, we were able to detect limited amounts of lipoylated H protein in the presence of malonate, several sulfur donors, and cofactors, Finally, we present a scheme outlining the new biochemical pathway of fatty acid and lipoic acid synthesis in plant mitochondria.