| Project/Area Number |
09670132
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
General medical chemistry
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| Research Institution | The University of Tokushima |
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Principal Investigator |
FUJIWARA Kazuko the University of Tokushima, the Institute for Enzyme Research, assistant professor, 分子酵素学研究センター, 助教授 (20108880)
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| Project Period (FY) |
1997 – 1998
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| Project Status |
Completed (Fiscal Year 1998)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1998: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1997: ¥2,700,000 (Direct Cost: ¥2,700,000)
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| Keywords | lipoyltransferase / lipoate-activating enzyme / lipoic acid / chromosomal mapping / glycine cleavage system / alpha-ketoacid dehydrogenase complex / cloning / リボ酸転移酵素 / リボ酸 / グリシン開裂酵素 / ミトコンドリア / 発現 / cDNA / lipoate-protein ligase |
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| Research Abstract |
Lipoic acid is a prosthetic group of H-protein of the glycine cleavage system and the acytransferase components of the pyruvate, alpha-ketoglutarate, and branched chain alpha-ketoacid dehydrogenase complexes. In mammals, lipoic acid is activated to lipoyl-AMP by lipoate-activating enzyme and then the lipoyl moiety is transferred to the proteins by the lipoyltransferase.
1) We cloned a lipoyltransferase cDNA from a bovine liver cDNA library and determined the nucleotide sequence. The predicted amino acid sequence showed 35% identity with that of Escherichia coli lipoate-protein ligase A.It was suggested that lipoyltransferase I and II, isoforms found in bovine liver, were derived from the same translated products but processed differently.
2) Lipoyltransferase had an affinity for selenolipoyl-AMP and transfered the selenolipoyl moiety to bovine apoH-protein comparable to lipoyl-AMP.Reaction rates of overall and partial glycine cleavage reactions with selenolipoylated and lipoylated H-protein were compared. The results well reflected the difference of redox potential between diselenide bond and disulfide bond.
3) We cloned human lipoyltransferase cDNA and genomic DNA.Tissue distribution of the mRNA of lipoyltransferase showed good corelation with those of lipoate-dependent proteins, suggesting a possibility of an efficient lipoylation of the proteins in the tissues.
4) We have partially purified lipoate-activating enzyme from bovine liver mitochondria. The research for the enzyme is now in progress.
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