Identification and expression of a rat fatty acid elongase involved in the biosynthesis of C18 fatty acids
Identification and expression of a rat fatty acid elongase involved in the biosynthesis of C18 fatty acids
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DOI：
10.1271/bbb.66.613
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发表时间：
2002-03-01
影响因子：
1.6
通讯作者：
Suzuki, O
中科院分区：
文献类型：
--
作者：
Inagaki, K;Aki, T;Suzuki, O
脂肪酸合酶生成的棕榈酸（C16:0）大部分通过碳链延伸转化为硬脂酸（C18:0）。在这里，我们描述了一种大鼠肝酶rELO2的克隆和表达，rELO2可能在冷凝反应中负责C16:0的延伸。在酵母Saccharomyces cereviside中的异源表达实验表明，rELO2对C16:0有伸长活性，对C18:0和低去饱和度脂肪酸也有较小程度的伸长活性。这与HELO1的大鼠同源物rELO1不同，rELO1较好地催化了C16-C20的单不饱和脂肪酸和多不饱和脂肪酸的延伸。Northern的分析表明，在禁食和再喂食无脂肪饮食的大鼠的循环中，肝细胞中rELO2的表达被激活，而不是rELO1。在这些条件下，rELO1在各种组织中组成性地表达，但在肝脏中主要检测到rELO2转录本。
A major part of the palmitic acid (C16:0) generated by fatty acid synthase is converted into stearic acid (C18:0) via carbon chain elongation. Here, we describe the cloning and expression of a rat hepatic enzyme, rELO2, responsible for the elongation of C16:0, presumably at the condensing reaction. Heterologous expression experiments in a yeast, Saccharomyces cereviside, demonstrated the elongation activity of rELO2 on C16:0 and to a lesser extent, C18:0 and fatty acids with low desaturation degree. This was distinct from that rELO1, a rat homolog of HELO1, which preferably catalyzed the elongation of mono- and polyunsaturated fatty acids of C16-C20. The Northern analysis showed that the expression of rELO2, but not rELO1, in hepatocytes was activated by the cycles of fasting and refeeding rats on a fat-free diet. Under these conditions, the rELO1 was expressed constitutively in various tissues but the rELO2 transcripts were detected predominantly in liver.