1989 Fiscal Year Annual Research Report

光活性化酵素の活性調筋機構の生理学的解析

Research Project

Project/Area Number	63540540
Research Institution	Teikyo University
Principal Investigator	臼田秀明帝京大学, 医学部, 助教授 (90112755)
Keywords	C_4光合成 / 酵素の光活性化 / ピルジシ酸リン酸ジキナ-ゼ / リンゴ酸脱水素酵素 / ATP / NADP / ADP / Thermodynamically active
Research Abstract	C_4植物の葉肉細胞葉緑体では光強度の増加に伴ってPyruvate,Pidikinase(PPDK)とNADP-malate dehydrogenase(NADP-MDH)の活性が光合成活性の増加に伴って促進されることが知られている。酵素の活性-不活化機構は、PPDKではリン酸化一脱リン酸化、NADP-MDHでは酸化一還元に依るとされている。in vitroの実験から[ADP]、アデニレ-トエナジ-チャ-ジ(AEC)の変化が、{[NADP]、thioredoxinの酸化還元状態の変化が}、光の強度の変化にともなってin vivoで起こり、PPDKと{NADP-MDH}の活性を調節していると提唱されている。しかし、in situでのPPDK,NADPーMDHの活性変化とそれらの調節因子と考えられているものの変化を同時に測定した研究は全くなされていない。そこでトウモロコシ葉の様々の光強度におけるPPDK,NADP-MDH活性とATP,ADP,AMP,NADP,NADPHの葉肉細胞葉緑体でのレベルを測定した。その結果、1)PPDK活性と[ADP],ATP/ADP比,AECの間には有意な相関は認められなかった。2)NADP-MDHの活性とNADP(NADPH),NADPH/NADP比の間には弱いが有意な相関が認められた。これらのことと既知の知見を整合性をもって説明するためにはthermodynamicallyにactiveなADP(NADP)があり、thermodynamicallyにactiveなADP(NADP)が光強度の減少に伴って増加すると考えられた。このことを実証するために再構成系の実験を行ったところ、上記の仮説を支持する結果が得られた。即ち、ストロマ系では光強度の違いをthermodynamicallにactiveなADP(NADP)のレベルの変化として感知しストロマ系の酵素活性を調節していると考えられる。

Research Products

(7 results)

All Other

All Publications (7 results)

[Publications] Usuda,H.: "Non aqueous purification of maize mesophyll chloroplasts." Plant Physiol.87. 427-430 (1988)
[Publications] Usuda,H.: "Adenine nucleotide levels,the redox state of the NADP system and assimilatory force in nonagueously purified mesophyll chloroplasts from maize leaves under different light intersifies." Plant Physiol.88. 1461-1468 (1988)
[Publications] Usuda,H.: "Light and C_4 photosynthesis.How can the stromal system sense differences in light intersity to adjust its activeities to the overall flux?" Bot.Mag.Tokyo. (1990)
[Publications] Usuda,H.: "How can the C_4 stromal system sense differences in light intensity to adjust its activities to the overall flux?" Prcceedings of VIIIth International Congress on Photosynthesis.(1990)
[Publications] Yokota,A.: "The in vivo functioning forms of Ribulose 1.5-bisphosphate carboxylase/oxygenase in plants." Prcceedings of VIIIth International Congress on Photosynthesis.(1990)
[Publications] Sawada,S.: "Regulation of ribulose-1.5-bisphosphate carboxylase activity in response to changes in source/sink balance in sigle-rooted soybean leaves." Plant Cell Physiol. (1990)
[Publications] Imaizumi,N.: "changes in the rate of photosynthesis during grain filling and activities of enzymes associated with photosynthetic carbon metabolism in rice panicles." Plant Cell Physiol.

1989 Fiscal Year Annual Research Report

光活性化酵素の活性調筋機構の生理学的解析

Principal Investigator

臼田 秀明 帝京大学, 医学部, 助教授 (90112755)

Research Products

[Publications] Usuda,H.: "Non aqueous purification of maize mesophyll chloroplasts." Plant Physiol.87. 427-430 (1988)

[Publications] Usuda,H.: "Adenine nucleotide levels,the redox state of the NADP system and assimilatory force in nonagueously purified mesophyll chloroplasts from maize leaves under different light intersifies." Plant Physiol.88. 1461-1468 (1988)

[Publications] Usuda,H.: "Light and C_4 photosynthesis.How can the stromal system sense differences in light intersity to adjust its activeities to the overall flux?" Bot.Mag.Tokyo. (1990)

[Publications] Usuda,H.: "How can the C_4 stromal system sense differences in light intensity to adjust its activities to the overall flux?" Prcceedings of VIIIth International Congress on Photosynthesis.(1990)

[Publications] Yokota,A.: "The in vivo functioning forms of Ribulose 1.5-bisphosphate carboxylase/oxygenase in plants." Prcceedings of VIIIth International Congress on Photosynthesis.(1990)

[Publications] Sawada,S.: "Regulation of ribulose-1.5-bisphosphate carboxylase activity in response to changes in source/sink balance in sigle-rooted soybean leaves." Plant Cell Physiol. (1990)

[Publications] Imaizumi,N.: "changes in the rate of photosynthesis during grain filling and activities of enzymes associated with photosynthetic carbon metabolism in rice panicles." Plant Cell Physiol.

臼田秀明帝京大学, 医学部, 助教授 (90112755)