1991 Fiscal Year Final Research Report Summary
Studies on Cyanide-Resistant Respiration in yeast, Hansenula anomala
| Project/Area Number |
02680162
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
代謝生物化学
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| Research Institution | Niigata College of Pharmacy |
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Principal Investigator |
YOSHIMOTO Akio Ph.D Niigata College of Pharmacy Professor, 衛生薬学科, 教授 (60025690)
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| Co-Investigator(Kenkyū-buntansha) |
SAKAJO Sigeru Ph,D Niigata College of Pharmacy Assistant, 衛生薬学科, 助手 (10201518)
MINAGAWA Nobuko Ph,D Niigata College of Pharmacy Assistant, 衛生薬学科, 助手 (90113026)
KOMIYAMA Tadazumi Ph,D Niigata College of Pharmacy Assistant Professor, 衛生薬学科, 助教授 (80133461)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Hansenula anomala / Cyanide-resistant respiration / Superoxide anion radical / Radical scavengers / Role of Fe^<2+> in cyanide-resistant respiration / Unsaturated fatty acids / Cation ionophores |
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| Research Abstract |
(1) Mitochondria exihibiting cyanide-resistant respiration were isolated from Hansenula anomala incubated in the presence of antimycin A or a certain sulfur-compounds. Analysis of mitochondrial proteins by gel electrophoresis indicates that a 36 kDa protein was induced. When the cells were labeled with ^<35>S-methionine in the presence of both antimycin A and CCCP, the radioactivity was incorporated into a 39 kDa mitochondrial protein. Upon removal of CCCP, this protein was processed into a 36 kDa form, suggesting that the 39 kDa protein is the precursor of 36 kDa protein.
(2) The antimycin A-dependent induction of cyanide-resistant respiration was completely repressed by specific chelators for Fe^<2+>. The addition of Fe^<2+> to the cells resulted in a rapid increase in cyanide-resistant respiration activity, suggesting that Fe^<2+> is involved in the reaction mechanism of this respiration.
(3) Since a plant-like alternative oxidase was reported to serve as a sole terminal oxidase of Tr
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ypanosoma brucei brucei, the studies on the specific inhibitors of cyanide-resistant respiration have taken on a great sibnificance for the chemotherapy of trypanosome infections. We found specific inhibitory effects on cyanide-resistant respiration of some fatty acids with nonconjugated duoble bonds, radical scavengers such as CoQ derivatives and flavonoids, and cation ionophores.
(4) Q_i site inhibitors such as antimycin A induce O_2 generation in respiring cyanide-sensitive mitochondria of H. anomala. Radical scavengers suppressed O_2 generation, and inhibited both the induction of cyanide-resistant respiration and the appearance of the mitochondrial 36 kDa protein. These results suggest that O_2 is involved in the induction of cyanide-resistant respiration.
(5) A cDNA for mRNA induced by antimycin A was cloned. The nucleotide sequence revealed a long open reading frame of 342 codons encoding a protein. Immunoblotting showed that the 36 kDa protein localized in mitochondria was a mature form of the protein encoded by the cDNA. Less
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