69 脂肪酸生合成反応の立体化学 : 脂肪酸鎖上水素の立体配置

概要

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The steric course of the enoyl reduction catalyzed by fatty acid synthetases was investigated with deuterium as a tracer. Deuterium labeled decanoic acids were synthesized by Escherichia coli enoyl-ACP reductase from various deuterium sources. Then they were subjected to the action of acyl-CoA oxidase, which had been previously shown to catalyze the anti elimination of the pro-2R and pro-3R hydrogens of acyl-CoA. The deuterium contents of saturated and 2,3-dehydrofatty acids were analyzed by GC/MS. Deuterium labeled fatty acids were synthesized from [2-^2H_2] malonyl-CoA or in the presence of stereo-specifically deuterium labeled NAD(P)H by fatty acid synthetases from yeast, Brevibacterium ammoniagenes and rat liver. The steric positions of deuterium atoms were analyzed by the method using acyl-CoA oxidase. These results suggested that the hydrogen of NAD(P)H was incorporated via a 3-Si attack by the enzyme from E. coli and B. ammoniagenes and via a 3-Re attack by the enzyme from rat liver, and the hydrogen of water was incorporated via a 2-Re attack by E. coli and B. ammoniagenes enzyme and via a 2-Si attack by yeast and rat liver enzyme. The stereochemistry of the formation of oleic acid by B. ammoniagenes fatty acid synthetase was also investigated.
天然有機化合物討論会の論文
1981-09-10