34 アミノ酸類を前駆体とするモノテルペノイドの生合成経路

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No or negligible incorporation of leucine, isoleucine, and valine into monoterpenoids in higher plants has been reported. We tested the incorporation of radioisotopically labeled leucine, valine, and alanine into linalool in Cinnamomum Camphora and into geraniol and citronellol in Pelargonium roseum. The amino acids were undoubtedly incorporated into these monoterpenoids. In the incorporations, more than 70% of the total radioactivities resided in the DMAPP-derived moiety after uptake of leucine and valine, whereas less than 40% in the DMAPP-derived moiety after uptake of alanine and mevalonic acid. We also examined the effect of inhibition of the IPP isomerase activity on the distribution of radioactivity after uptake of the amino acids. The predominant location of radioactivity in the DMAPP-derived portion was observed when leucine-4,5-^3H_2 had been fed to Cinnamomum Camphora in the presence of iodoacetamide, which is known as the inhibitor. Thus, it was found that leucine and valine may participate in the biosynthesis of monoterpenoids by their conversion to the DMAPP-derived portion of the monoterpenoids through any pathway other than the mevalonoid pathway. On the contrary, alanine is first metabolized to acetyl-CoA, which is converted preferentially to the IPP-derived portion of the monoterpenoids via mevalonic acid.
天然有機化合物討論会の論文
1979-09-20