1987 Fiscal Year Final Research Report Summary
Regulatory Mechanism by Nitrogen of Gene Expression of Enzymes Involved in Photosynthesis and Nitrogen-Assimilation Pathways
| Project/Area Number |
61480056
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
応用生物化学・栄養化学
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| Research Institution | Nagoya University |
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Principal Investigator |
SUGIYAMA Tatsuo Nagoya University, Professor (372550023453), 農学部, 教授 (50023453)
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| Co-Investigator(Kenkyū-buntansha) |
SASAKAWA Hideo Nagoya University, Assistant (462240115572), 農学部, 助手 (40115572)
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| Project Period (FY) |
1986 – 1987
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| Keywords | Maize / RubisCO / PEP carboxylase / pyruvate-Pi dikinase / glutamine synthetase,GOGAT / mRNA,carbon assimilating enzyme / nitrogen assimilating enzyme / glutamate synthase / Pi dikinase / pyruvate |
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| Research Abstract |
The results obtained in this project were summarized as follows.
1. The regulation of gene expression by nitrogen of carbon assimilating enzymes in maize leaf was studied by examining partitioning of nitrogen into rubisCO, PEP carboxylase, and pyruvate, Pi dikinase in transitional state during supplementing nitrogen to nitrogen deficient plant seedlings grown under near optimal light and temperature conditions. In a fully developed youngest leaf a differential accumulation of protein and mRNA was observed among these three enzymes. Based upon the data PEP carboxylase was judged as a most limiting enzyme to photosynthesis in maize leaf. An evidence was also provided to suggest that nitrogen is a regulatory factor essential for the light-stimulation of accumulation of mRNA and protein for these three enzymes.
2. Aspartate aminotransferase was purified from the mesophyll cells of Panicum maximum trichoglume , a PEP carboxykinase type of C_4 plant. Partial characterization of the enzyme which appears to involve photosynthetic carbon assimilation was achieved and its specific polyclonal antibody was prepared. Using this antibody the complementary cDNA of this enzyme was prepared from DNA library of mRNAs derived from Eleusine coracana, a NAD- malic enzyme type of C_4 plant. Also, antibodies against Gln synthetase and GOGAT were prepared.
3. Light/dark regulation of maize leaf PEP carboxylase was studies and its possible mechanism was proposed based upon analysis of dark-inactivated and light-activated forms.
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