1995 Fiscal Year Final Research Report Summary
Role of Selenium in Protection against Oxidative Stress
| Project/Area Number |
05044184
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Institution | Kitasato University |
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Principal Investigator |
IMURA Nobumasa Kitasato University, Professor, 薬学部, 教授 (70012606)
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| Co-Investigator(Kenkyū-buntansha) |
TOYODA Haruka Tokyo University, 医科学研究所, 講師 (10197973)
XIA Yiming Chinese Academy of Preventive Medicine, 栄養食品衛生研究所, 室長
BURK Raymond f Vanderbilt University, 医学部, 教授
HIMENO Seiichiro Kitasato University, 薬学部, 講師 (20181117)
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| Project Period (FY) |
1993 – 1995
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| Keywords | selenium / selenoproteins / oxidative stress / radical scavenger / transformants / species difference |
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| Research Abstract |
Selenium, an essential trace element, is considered to act as an antioxidant in animal body since it constitutes the active site of glutathione peroxidase (GSH-Px). Recently, several selenoproteins other than GSH-Px were identified. Selenoprotein P is a newly recognized selenoprotein that contains about 60% of selenium in the plasma.
In this international collaboration study, US and Japanese researchers worked together to characterize selenoprotein P using techniques of protein chemistry. Several isoforms of selenoprotein P purified from rat plasma were identified and characterized. All the isoforms were able to be bound to a heparin Sepharose column, but the elution pattern by pH gradient was different among these isoforms. This suggested that each isoform of selenoprotein P may have a different binding affinity to proteoglycans located outside the plasma membrane surrounding the blood vessels. Furthermore, we isolated one of the isoform and determined its C-terminal amino acid sequenc
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e. This isoform was truncated at the site just upstream of the second UGA codon, suggesting an alternative usage of the second in-frame UGA codon for selenocysteine insertion and termination of the translation.
In China, human diseases of both selenium deficiency and selenium intoxication were observed. A Japanese researcher visited the area of selenium poisoning for the first time by this grant. A difference in health effect of selenium was recognized between two villages of this area, probably due to the difference in the chemical form of selenium ingested by villagers. Japanese and Chinese sides are now working together for the development of analytical method of selective determination of organic and inorganic selenium.
To assist Chinese researchers for the establishment of a laboratory for molecular biological studies on the mechanism of selenosis and selenium deficiency-related diseases, both Japanese and US researchers provided technical assistance and various kinds of cDNA probes. Less
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