| Budget Amount *help |
¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 2002: ¥1,000,000 (Direct Cost: ¥1,000,000)
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| Research Abstract |
1. Examination of the reaction condition of the oxidized cystine formation : Metal-ascorbic acid or metal-hydrogen peroxide systems (Fenton reaction) were examined for the formation of oxidized cystine in various proteins. Insulin couldn't used for this reaction system because of its unstable nature, but serum proteins were able to detect the oxidized cystine with the amino acid analysis even though in 37℃ for 24 hours.
2. Examination of oxidative factors for the oxidized cystine formation : Hydroxyl radical generated by Fenton reaction (copper ion + hydrogen peroxide) was the most effective oxidizing agent for the formation of oxidized cystine in oxidative protein. However, high concentration of copper ion was hard to exist in human body except a certain illness (Wilson disease). So the oxidative factors were re-examined under the non-metal catalyzed conditions. As a result, lipid peroxide (LOOH) caused the oxidation of cystine and the other sulfur-containing amino acids with the best efficiency. Oxidized cystine and oxidized methionine (= methionine sulfoxide) were formed with LOOH about 5 times higher selectivity than hydrogen peroxide.
3. Secondary biological oxidative damages by oxidized cystine : Oxidatively modified protein, which contains oxidized cystine, was found to react with thiols (glutathione, etc.) to generate reactive oxygen species (ROS). And this combination made the fragmentation of native protein and DNA by generating superoxide (O2).
4. The redox control by wasabi isothiocyanate : The food factor, which can generate ROS from the reaction with glutathione, was screened. The Allium vegetables and the crusifer vegetables were selected. In particular, wasabi isothiocyanate (6- methylsulfinylhexyl isothiocyanate) made great amount of ROS in RL34 cells.
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