東京工科大学 研究報告等

藤沢 章雄
所属  応用生物学部 応用生物学科
職種  教授
言語種別
英語
発行・発表の年月
2017年11月
形態種別
学術論文
査読
査読あり
標題
Parabanic acid is the singlet oxygen specific oxidation product of uric acid.
執筆形態
共著
掲載誌名
Journal of Clinical Biochemistry and Nutrition
出版社・発行元
Society for Free Radical Research Japan
巻・号・頁
61(3),169-175
担当範囲
Corresponding Author
著者・共著者
Iida S, Ohkubo Y, Yamamoto Y, Fujisawa A.
概要
Uric acid quenches singlet oxygen physically or reacts with it, but the oxidation product has not been previously characterized. The present study determined that the product is parabanic acid, which was confirmed by LC/TOFMS analysis. Parabanic acid was stable at acidic pH (<5.0), but hydrolyzed to oxaluric acid at neutral or alkaline pH. The total yields of parabanic acid and oxaluric acid based on consumed uric acid were ~100% in clean singlet oxygen production systems such as UVA irradiation of Rose Bengal and thermal decomposition of 3-(1,4-dihydro-1,4-epidioxy-4-methyl-1-naphthyl)propionic acid. However, the ratio of the amount of uric acid consumed to the total amount of singlet oxygen generated was less than 1/180, indicating that most of the singlet oxygen was physically quenched. The total yields of parabanic acid and oxaluric acid were high in the uric acid oxidation systems with hydrogen peroxide plus hypochlorite or peroxynitrite. They became less than a few percent in peroxyl radical-, hypochlorite- or peroxynitrite-induced oxidation of uric acid. These results suggest that parabanic acid could be an in vivo probe of singlet oxygen formation because of the wide distribution of uric acid in human tissues and extracellular spaces. In fact, sunlight exposure significantly increased human skin levels of parabanic acid.
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