量研学術機関リポジトリ「QST-Repository」は、国立研究開発法人 量子科学技術研究開発機構に所属する職員等が生み出した学術成果（学会誌発表論文、学会発表、研究開発報告書、特許等）を集積しインターネット上で広く公開するサービスです。 Welcome to QST-Repository where we accumulates and discloses the academic research results(Journal Publications, Conference presentation, Research and Development Report, Patent, etc.) of the members of National Institutes for Quantum Science and Technology.
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The availability of thiol compounds to generate superoxide by reducing molecular oxygen at hyperthermal temperature was investigated. The reaction properties of cysteine (Cys), N-acetyl-L-cysteine (NAC), reduced form glutathione (GSH), and homocysteine (HCS) were compared. A sulfur-containing amino acid, methionine (Met), biological hydrogen-donor, reduced beta-nicotinamide adenine dinucleotide (NADH), and reduced beta-nicotinamide adenine dinucleotide phosphate (NADPH) were also tested for comparison. An oxidative atmosphere, i.e. superoxide generation by the hypoxanthine-xanthine oxidase reaction, hydroxyl radical generation by X-ray irradiation, or direct one-electron oxidation by ferricyanide, was prepared in a reaction mixture containing 0.1 mM TEMPOL and 1 mM of the test compound, and the EPR signal decay profile of TEMPOL was observed. A reaction mixture containing 0.1 mM TEMPOL and 1 mM thiol compound, Cys, NAC, GSH, or HCS was incubated at 44DegreeC, and the EPR signal decay profile of TEMPOL was observed. Thiols can work as H-donors to the oxoammonium cation form and produce the hydroxyl amine form of TEMPOL in an oxidative atmosphere. Thiols can also irreversibly react with the oxoammonium cation. NAD(P)H could work only as an H-donor. Met did not show any reaction with TEMPOL. GSH and Cys can reduce molecular oxygen to form hydroperoxyl radical/superoxide at hyperthermal temperatures, but HCS and NAC cannot reduce molecular oxygen. GSH and Cys may possibly cause reductive stress, whereas NAC is a simple tractable antioxidant.
会議概要（会議名, 開催地, 会期, 主催者等）
Oxygen Radicals, Biology and Pathobiology of Oxygen Radicals from Cell Signaling and Detection to Therapy
Availability of thiol compounds to generate superoxide by reducing molecular oxygen
