Grant-in-Aid for General Scientific Research (A)
|Allocation Type||Single-year Grants |
|Research Institution||HIROSHIMA UNIVERSITY |
SUGA Takayuki Hiroshima Univ., Science, Professor, 理学部, 教授 (00033811)
AOKI Tadashi Suzugamine Women's College, Professor, 教授 (40112164)
OTA Shinji Hiroshima Univ., Education, Lecturer, 学校教育学部, 講師 (60185270)
IZUMI Shunsuke Hiroshima Univ., Science, Assistant, 理学部, 助手 (90203116)
MUNESADA Kiyotaka Hiroshima Univ., Science, Assistant, 理学部, 助手 (30166235)
HIRATA Toshifumi Hiroshima Univ., Science, Assistant Professor, 理学部, 助教授 (80033926)
荻原 和仁 広島大学, 理学部, 助手 (00194481)
深沢 義正 広島大学, 理学部, 助教授 (50004502)
山岡 究 広島大学, 理学部, 助教授 (40033815)
|Project Period (FY)
1986 – 1989
Completed (Fiscal Year 1989)
|Budget Amount *help
¥34,100,000 (Direct Cost: ¥34,100,000)
Fiscal Year 1989: ¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 1988: ¥4,000,000 (Direct Cost: ¥4,000,000)
Fiscal Year 1987: ¥5,000,000 (Direct Cost: ¥5,000,000)
Fiscal Year 1986: ¥21,000,000 (Direct Cost: ¥21,000,000)
|Keywords||Isoprenoid biosynthesis / Prenylation / Cyclization / Stereochemistry / Mechanism / Higher plants / Intermediate / Enzymology / プレニル鎖環化 / プレニル鎖延長過程 / 環化過程 / 酵素反応の立体化学 / 疎水性クロマイドグラフィー / 酵素系 / 異性化酵素阻害剤 / 二価金属イオン / プレニル鎖環化過程 / 水素脱離様式 / 縮合面の立体化学 / 異性化酵素阻割剤 / 酵素活性発現因子|
The stereochemistry and mechanism for the fundamental processes, especially prenylation and cyclization of the allylic chain, in the biosynthesis of isoprenoids were investigated as follows:
(1) "Geranyl diphosphate synthase" responsible for the prenylation between dimethylallyl diphosphate and isopentenyl diphosphate was first isolated from the leaves of Pelargonium roseum.
(2) "Polyprenyl diphosphate synthasell was partially purified from the leaves of Mallotus japonicus.
(3) Three novel polyprenols, possessing a phytyl residue, four to six internal (Z)-prenyl residues, and a Z a-terminal residue aligned in that order, were isolated from the leaves of soybean, Glycine max.
(4) ^<13>C NMR studies on the enzymatic reaction of geranyl diphosphate and isopentenyl diphosphate indicated that the prenylation involves "stepwise mechanism" via allylic cation as an intermediate.
(5) "Limonene synthasell responsible for the cyclization of geranyl diphosphate (GPP) to limonene was partially purified from the leaves of Mentha spicata and Citrus unshiu.
(6) Divalent metal cations, especially Mg^<2+> and Mn^<2+>, is essential for the enzymatic cyclization of GPP; the metal cation binds to the diphosphate moiety of GPP in a mole ratio of 1:1 in the initial stages of the cyclization and the chelation weakens the C_-O bond of the diphosphate to facilitate the elimination of the diphosphate group.
(7) The process for the cyclization involves the geranyl cation having anti- endo conformer under the steric control characteristic of the enzyme in the respective plants and then the allylic cation is led to the formation of the stereospecifically featured cyclic monoterpenoids.