That control by the analysis of the difficulty mechanism that a secondary living body by cystine oxidizes and the food factor

1.氧化胱氨酸形成的反应条件的检查：检查金属-抗坏血酸或金属-过氧化氢系统（芬顿反应）在各种蛋白质中氧化胱氨酸的形成。胰岛素因其不稳定性不能用于该反应体系，而血清蛋白在37℃下24 h仍能检测到氧化胱氨酸.氧化胱氨酸形成的氧化因素考察：芬顿反应（铜离子+过氧化氢）产生的羟基自由基是氧化蛋白中氧化胱氨酸形成的最有效氧化剂。然而，高浓度的铜离子很难在人体内存在，除非是某种疾病（Wilson病）。因此，在非金属催化条件下重新考察了氧化因素。结果表明，脂质过氧化物（LOOH）引起胱氨酸和其他含硫氨基酸的氧化效率最高。氧化胱氨酸和氧化甲硫氨酸（=甲硫氨酸亚砜）的形成与LOOH的选择性比过氧化氢高约5倍.氧化胱氨酸引起的二次生物氧化损伤：发现含有氧化胱氨酸的氧化修饰蛋白质与巯基（谷胱甘肽等）反应。以产生活性氧物质（ROS）。这种结合通过产生超氧阴离子（O2）使天然蛋白质和DNA发生断裂.异硫氰酸山葵的氧化还原调控：筛选出能与谷胱甘肽反应产生ROS的食物因子。选择了葱属蔬菜和十字花科蔬菜。特别地，异硫氰酸山葵（6-甲基亚磺酰基己基异硫氰酸酯）在RL 34细胞中产生大量的ROS。

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.