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CO_2 fixation and energy metabolism in a themophilic,aerobic autotroph

Research Project

Project/Area Number 62470122
Research Category

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

Allocation TypeSingle-year Grants
Research Field 発酵・醸造
Research InstitutionThe University of Tokyo

Principal Investigator

KODAMA Tohru  Faculty of Agriculture, the University of Tokyo ・ Professor, 農学部, 教授 (30011901)

Co-Investigator(Kenkyū-buntansha) IGARASHI Yasuo  Faculty of Agriculture, the University of Tokyo ・ Assistant professor, 農学部, 助手 (90114363)
Project Period (FY) 1987 – 1988
Project Status Completed (Fiscal Year 1988)
Budget Amount *help
¥6,100,000 (Direct Cost: ¥6,100,000)
Fiscal Year 1988: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1987: ¥5,000,000 (Direct Cost: ¥5,000,000)
KeywordsHydrogen bacteria / Thermophilic bacteria / Hydrogenase / Cytochrome C / Reductive carboxylic acid cycle / ATP / 高度好熱性菌
Research Abstract

In this research, we investigated energy metabolism and typical CO_2 fixation reaction in Hydrogenobacter thermophilus.
1. Energy metabolism in Hydrogenobacter thermophilus. By using cell lysate and membrane fraction, it was shown that cytochrome c_<552> was reduced by hydrogenase reaction. So, it was demonstrated that cytochrome c_<552> is a natural electron acceptor for the membrane-bound hydrogenase. In order to confirm the result, membrane-bound hydrogenase and cytochrome c_<552> were purified. The membrane-bound hydrogenase was purified by the following steps (1)Solubilization, (2)Hydrophobic chromatography, (3)Adsorption chromatography, and (4)Ion-exchange chromatography. Cytochrome c_<552> was purified by the following steps (1)Ion-exchange chromatography, and (2)Affinity chromatography. In vitro experiment showed that the purified hydrogenase reduces cytochrome c_<552> in the presence of detergents. Together with the fact that the terminal cytochrome in H. thermophilus is cytoch … More rome o, we clarified the electron transport system in H. thermophilus.
2. Typical CO_2 fixation reaction in H. thermophilus. H. thermophilus is known to fix CO_2 via a reductive carboxylic acid cycle. But, in two typical CO_2 fixation reactions (pyruvate synthase and -ketoglutarate synthase), the activities could not be measured in forward directions. To know what kind of reductant is involved in H. thermophilus, we tried to demonstrate the enzyme activity in forward direction. For that purpose, we obtained a partially purified puruvate synthase by ion-exchange chromatography and various reductants. To obtain a partially purified enzyme, the enzyme activity was assayed in reverse direction. As reductants, methylviologen, membrane extracts, and NAD(P)H were used. Unfortunately, under the various conditions we tried, we could not demonstrate the enzyme activity in forward direction. It is known that pyruvate synthase catalyzes isotope exchange reaction between NaH^<14>CO_3 and pyruvate. As the partially purified enzyme catalyzed this reaction, it became clear that pyruvate synthase really works in H. thermophilus. Less

Report

(3 results)
  • 1988 Annual Research Report   Final Research Report Summary
  • 1987 Annual Research Report
  • Research Products

    (11 results)

All Other

All Publications (11 results)

  • [Publications] Masaharu Ishii: Agric.Biol.Chem.51. 3139-3141 (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1988 Final Research Report Summary
  • [Publications] Masaharu Ishii: J.Bacteriol.

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1988 Final Research Report Summary
  • [Publications] Masaharu Ishii: Agric.Biol.Chem.51. 1695-1696 (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1988 Final Research Report Summary
  • [Publications] Masaharu Ishii: Agric.Biol.Chem.51. 1825-1831 (1987)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1988 Final Research Report Summary
  • [Publications] Masaharu Ishii: "Purification and Some properties of cytochrome C_<552> from Hydrogenobacter thermophilus" Agric. Biol. Chem.51. 1695-1696 (1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1988 Final Research Report Summary
  • [Publications] Masaharu Ishii: "The membrane bound hydrogenase reduces cytochrome C_<552> in Hydrogenobacter thermophilus strain TK-6" Agric. Biol. Chem.51. 1825-1831 (1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1988 Final Research Report Summary
  • [Publications] Masaharu Ishii: "Colony formation of Hydrogenobacter thermophilus on a plate solidified with GELRITE" Agric. Biol. Chem.51. 3139-3141 (1987)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1988 Final Research Report Summary
  • [Publications] Masaharu Ishii: "Purification and characterization of ATP: citrate lyase from Hydrogenobacter thermophilus TK-6" J. Bacteriol.

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1988 Final Research Report Summary
  • [Publications] Masaharu.Ishii: J.Bacteriol.

    • Related Report
      1988 Annual Research Report
  • [Publications] Masaharu.Ishii: Agric.Biol.Chem.51. 1695-1696 (1987)

    • Related Report
      1987 Annual Research Report
  • [Publications] Masaharu.Ishii: Agric.Biol.Chem.51. 1825-1831 (1987)

    • Related Report
      1987 Annual Research Report

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Published: 1987-04-01   Modified: 2016-04-21  

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