89(P2-19) クロロフィル・バクテリオクロロフィルの生合成(ポスター発表の部)  [in Japanese] 89(P2-19) Biosynthesis of Chlorophyll and Bacteriochlorophyll  [in Japanese]

We have synthesized ^<13>C-labeled precursors such as glycine, methionine and glutamic acid for the biosynthesis of porphyrinoid. We also established the regioselective synthesis of ^<13>C-labeled ALA (δ-aminolevulinic acid) in the same method from ^<13>C-labeled sodium acetate, and utilize these in the study of biosynthesis of chlorophyll and bacteriochlorophyll. L-[1-^<13>C]glutamic acid-incorporated chlorophyll showed ^<13>C-enriched peaks at sp^2 region. This result shows ring carbons are derived from glutamic acid by Beale route in E. gracilis. Incorporation of [2-^<13>C]glycine to E. gracilis gave chlorophyll labeled at 10b methyl ester (52.4 ppm). In the same way, L-[^<13>CH_3] methionine was incorporated and showed enriched peak at 52.4 ppm. It indicates glycine was metabolized into methionine and was incorporated into one side chain of chlorophyll in E. gracilis. [2-^<13>C]glycine-incorporated bacteriochlorophyll showed ^<13>C-enriched peaks at sp^2 region. Also the feeding experiment of [5-^<13>C]ALA into bacteriochlorophyll showed the same result. It indicates ALA was derived from glycine by Shemin route in R. spheroides. Furthermore feeding experiment of ^<13>C-labeled ALA in 50% D_2O medium and that of ^<13>C, ^2H-doubly labeled ALA into bacteriochlorophyll showed α,β isotope-shifted peaks at ring carbons. It showes ring protons at C5a, C3, C4, C8 position of bacteriochlorophyll are derived from water in R. spheroides.