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Molecular Mechanism of Photoregulation of a Plant Enzyme by Phosphorylation/Dephosphorylation

Research Project

Project/Area Number 02808034
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field 代謝生物化学
Research InstitutionKyoto University

Principal Investigator

IZUI Katsura  Kyoto Univ., Fac. of Sci. ASSoc. Prof., 理学部, 助教授 (20025414)

Project Period (FY) 1990 – 1991
Project Status Completed (Fiscal Year 1991)
Budget Amount *help
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 1991: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1990: ¥1,000,000 (Direct Cost: ¥1,000,000)
KeywordsC_4 photosynthesis / Proteinkinase / Maize / Phosporylagtion of protein / Phosphoenlopyrurate carboxylase / Transduction of light signal / Calcium ion / 光情報 / C_4光合成 / タンパク貭のリン酸化 / リン酸化 / 光による活性調節
Research Abstract

Phosphoenolpyruvate carboxylase(PEPC)involved in C4 photosynthesis is known to be activated under light conditions and deactivated under dark conditions. This photoregulation is mediated by phosphorylation of PEPC. The study was undertaken to obtain a clue to the molecular mechanism for this process. Previously we found that PEPC of maize(a C4 plant)can be phosphorylated by a mammalian cyclic AMP-dependent protein kinase and is l e dto the activated state similarly to the activation in vivo. Furthermore, we identified the site of phosphorylation to be S e r - 1 4. A protein kinase which phosphorylates PEPC(PEPC-PK)was partially purified from maize green leaves and the site of phosphorylation was shown to be identical with the site phosphorylated by the mammalian protein kinase. A recombinant maize PEPC produced in E. coli cells, which is assumed to be free of phosphorylation was prepared and its kinetic properties were compared with the dark-form PEPC(40% phosphorylated)prepared from maize leaves. Kinetic propertied such as Km for PEP and Ki for malate were not significantly different from one another. To characterize PEPC-PK, a series of PK inhibitors with different specificities were tested and it was found that the enzyme was strongly inhibited by the inhibitor for Ca^<2+>- calmodulin-dependent PK such as myosin light chain kinase. Furthermore, the enzyme was inhibited by EGTA and the inhibition was relieved by the addition of Ca^<2+>. These results strongly suggest that the light signal is transduced to PK by elevating the intracellular concentration of Ca^<2+>. Molecular characterization of PK and cloning of its cDNA is now under progress.

Report

(3 results)
  • 1991 Annual Research Report   Final Research Report Summary
  • 1990 Annual Research Report
  • Research Products

    (10 results)

All Other

All Publications (10 results)

  • [Publications] K.Terada: "Maize leaf phosphoenolpyruvate carboxylase:Phosphorylation of Ser-15 with a mammalian cyclic AMP-dependent protein kinase diminishes sensitivity to inhibition by malate" FEBS Lett.259. 241-244 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] S.Yanagisawa: "Production of active phosphoenolpyruvate carboxylase of Zea mays in Escherichia coli encoded by a full-length cDNA" Agr.Biol.Chem.54. 241-243 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 泉井 桂: "C4光合成の炭酸固定酵素とその遺伝子" 化学と生物. 28. 714-722 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] N.Ogawa: "A Ca^<2+>-dependent protein kinase phosphorylates phosphoenolpyruvate carboxylase in maize" FEBS Lett.(1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] K. Terada, T. Kai, S. Okuno, H. Fujisawa & K. Izui: "Maize leaf phosphoenolpyruvate carboxylase : Phosphorylation of Ser-15 with a mammalian cyclic AMP-dependent protein kinase diminishes sensitivity to inhibition by malate" FEBS Lett.259. 241-244 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] S. Yanagisawa & K. Izui: "Production of active phosphoenolpyruvate carboxylase of Zea mays in Escherichia coli encoded by a full-length cDNA" Agr. Biol. Chem.54. 241-243 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] K. Izui: "The CO_2-fixation enzyme and its gene involved in the C4 photosynthesis ---Structure, regulation and evolution---" Kagaku to Seibutsu (in Japanese). 28. 714-722 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] N. Ogawa, S. Okumura & K. Izui: "A Ca^<2+>-dependent protein kinase phosphorylates phosphoenolpyruvate carboxylase in maize" FEBS Lett.(1992)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 泉井 桂: "C4光合成の炭酸固定酵素とその遺伝子ー構造・調節・進化" 化学と生物. 28. 714-722 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] S.Okumura: "Effect of phosphorylation of maize phosphoenolpyruvate carboxylase produced in recombinant E.coli colls on kinetic properties"

    • Related Report
      1990 Annual Research Report

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Published: 1990-04-01   Modified: 2016-04-21  

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