PRODUCTION OF USEFUL COMPOUND COUPLED TO RESPONSE OF ENDOGENOUS STRESS

与内源应力响应相关的有用化合物的产生

• 批准号: 04660089
• 负责人: SHIBATA Hitoshi
• 金额: $ 1.22万
• 依托单位: SHIMANE UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04660089/
• 关键词: Stress response; Mevalonic acid; Stevia rebaudiana; Stevia sweetner; Endogenous stress; ステビア; ステビオサイド; 配糖体; 配糖化酸素

Natural sweet compound accumulated in Stevia rebaudiana Bertoni are glucosides whose aglycone is steviol. Kaurenoic acid is the precousor of the plant growth regulator, gibellelic acid, and as well as of steviol. Kaurenoic acid and many functional compounds such as sterols, carotenoids, quinones and phytol-moiety of chlorophylls are synthesized via mevalonic pathway whose rate-limiting enzyme is hydroxy methyl-glutaryl-CoA (HMG-CoA) reductase.To evaluate the possiblity that S.rebaudiana synthesize abonormal amonunt of mevalonic acid, and metabolize it to non-functinal stevol via kaurenoic acid avoiding the accumulation of giberellic acid, we compared HMG-CoA reductase activities in isolated chloroplasts, microsomal and soluble fraction from S.rebaudiana, Solidago altissima L.and Spinach leaves. Although specific activities of HMG-CoA reductase detected in microsomal and soluble fractions from three different kinds of leaves were almost the same level, the activity in chloroplasts were 200-300-fold and 8-10-fold higher than that from spinach and that from S.altissima. Km values for the substrate were the same order and the inhibition by mevalonin, a specific inhibitor for HMG-CoA reductase caused similar inhibition. These results indicate that S.rebaudiana synthesizes higher amount of mevalonic acid which is endogenous stress, and metabolizes it to kaurenoic acid and then to steviol avoiding accumulation of more gibellelic acid. As steviol is hydrophobic nature, glucosylation to its skeletone endowes water-solubility making it possible to across biomembrenes. Thus the accumulation of sweet stevioside compounds in S.rebaudia is concluded to be a response to overcome the highly accumulated mevalonic acid.

甜菊中积累的天然甜味化合物是以甜菊醇为苷元的糖苷类化合物。贝壳杉烯酸是植物生长调节剂赤藓糖酸和甜菊醇的前体。贝壳杉烯酸和许多功能性化合物如甾醇、类胡萝卜素、醌类和叶绿素的植醇部分都是通过以羟甲基戊二酰辅酶A（HMG-CoA）还原酶为限速酶的甲羟戊酸合成途径合成的，为了探讨甜菊合成甲羟戊酸异常并通过贝壳杉烯酸代谢为非功能性甜菊醇的可能性，我们比较了从甜菊、一枝黄花和菠菜叶片中分离的叶绿体、微粒体和可溶性组分中的HMG-CoA还原酶活性。3种叶片微粒体和可溶性组分中HMG-CoA还原酶的比活性基本相同，但叶绿体中的HMG-CoA还原酶比活性分别比菠菜和高羊茅高200-300倍和8-10倍。底物的Km值是相同的顺序，并且HMG-CoA还原酶的特异性抑制剂甲羟戊酸的抑制引起类似的抑制。这些结果表明，甜菊合成更高量的甲羟戊酸（内源胁迫），并将其代谢为贝壳杉烯酸，然后代谢为甜菊醇，避免积累更多的赤藓糖酸。由于甜菊醇是疏水性的，因此其葡糖基化为它的异黄酮赋予了水溶性，使得它可以跨越生物膜。因此，甜菊苷化合物在甜菊中的积累被认为是克服高度积累的甲羟戊酸的反应。

项目成果

河野、柴田、安達、田中: "Production by reactions on nitrite with hydrogen peroxide at acid pH and its bacterial effect on Escherichia coli." Archievs of Biochemistry and Biophysics. (印刷中). (1994)

Kono、Shibata、Adachi、Tanaka：“在酸性 pH 条件下亚硝酸盐与过氧化氢的反应及其对大肠杆菌的细菌作用”（Archievs of Biochemistry and Biophysicals）（1994 年出版）。

柴田、馬場、落合: "Near-UV irradiation induces shock proteins in Anacystis nidulans R-2." Plant and Cell Physiology. 32. 771-776 (1991)

Shibata、Baba 和 Ochiai：“近紫外线照射诱导 Anacystis nidulans R-2 中的休克蛋白。” 植物和细胞生理学 32. 771-776 (1991)。

柴田、馬場: "Shock protein synthesis bynear-UV irradiation in Anacystis nidulans R-2." Research in Photosynthesis,edited by N.Murata Kluwer Academic Publishers,Volume IV.4. 553-556 (1992)

Shibata, Baba：“Anacystis nidulans R-2 中近紫外线照射的休克蛋白合成”，N.Murata Kluwer 学术出版社编辑，第 IV.4 卷（1992 年）。

柴田: "近紫外線による活性酸素の生成と植物細胞の応答" 「環境変動と植物・微生物の生活-紫外線を中心として」所収 東北大学遺伝生態研究センター刊、IGEシリーズ. 15. 3-15 (1992)

柴田：“近紫外线产生的活性氧与植物细胞的反应”收录于东北大学遗传生态学研究中心出版的《环境变化与植物和微生物的生命——聚焦紫外线》，IGE系列第15期。 3-15 (1992))

H.Shibata and K.Baba: "Shock protein synthesis by near-UV in Anacystis nidulans R-2" "Research in Photosyn thesis" edited by N.Murata, Kluwer Academic Publishers. Volume IV. 553-556 (1992)

H.Shibata 和 K.Baba：“Anacystis nidulans R-2 中近紫外光合成休克蛋白”“光合作用论文研究”，由 N.Murata 编辑，Kluwer 学术出版社。