国際学会といっても、何も威張れるわけではなく、お金を払って、それ相応の研究内容を発表していれば、断られることはない。ようするに、中身の問題である。研究者同士の評価の問題である。

Biomarkers of Oxidative Stress in Health and Diseases

January 16-19, 2008 Senri Life Science Center, Osaka, Japan

Yoji Kato1, Shinsuke Hisaka2, Akihiro Yoshida3, Yoshiko Fukuchi4, Michitaka Naito4, Wakako Maruyama5, Noritoshi Kitamoto1, Toshihiko Osawa2
1 School of Human Science and Environment, University of Hyogo, 1-1-12 Shinzaike-honcho, Himeji, Hyogo 670-0092, 2 Nagoya University Graduate School of Bioagricultural Sciences, 3 Nakatsugawa Municipal Hospital, 4 Sugiyama Jogakuen University, 5 National Center for Geriatrics and Gerontology

Corresponding author: Yoji Kato

Hexanoyl-lysine (HEL) was identified from the reaction of linoleic acid hydroperoxides with a protein, as an omega-6 fatty acid-derived lysine adduct (J. Biol. Chem. 1999). In this study, we have reported that propanoyl-lysine (propionyl-lysine, PRL), as an oxidized omega-3 fatty acid-derived lysine adduct, was quantified from human urine by a liquid chromatography-quadruple tandem mass spectrometer (LC/MS/MS) with isotopic dilution method. The amounts of urinary PRL and HEL in diabetic urines were higher than those of control human urines. Moreover, the monoclonal antibody to PRL has been prepared and characterized. Using the specific anti-PRL antibody, the presence in atherosclerotic plaque of cholesterol-fed rabbit has been confirmed immunohistochemically. These lipid-lysine amide-type adducts family may be useful biomarkers for oxidative stress in vivo.

BOSHD2008について

The 4th Joint Meeting of the Society for Free Radical Research Australasia and Japan (SFRR A+J)
1-5 Dec. 2007, Kyoto University

学会会場となった時計塔記念館（という名前だったような）Platelets release serotonin (5-hydroxytryptamine, 5-HT) at sites of inflammation. Often neutrophils are present with platelets and produce superoxide and hydrogen peroxide via their NADPH oxidase. Neutrophils also release the heme enzyme myeloperoxidase (MPO), which use hydrogen peroxide to oxidize chloride to hypochlorous acid. It also oxidizes numerous other substrates, including serotonin. Previously, we have shown that MPO oxidizes serotonin to tryptamine-4,5-dione (TD) and that it aggregates proteins. We propose that at sites of inflammation MPO will produce TD, which will react with biomolecules, particularly thiols. To confirm this proposal, we examined the modification of thiols by serotonin in the presence of MPO and xanthine oxidase (XOD). 5-HT was efficiently oxidized by MPO and XOD. In the absence of thiol, both TD and the dimer of 5-HT (5,5'-dihydroxyl-4,4'-bitryptamine) were generated. In the presence of N-acetylcysteine (NAC), the 5-HT-dimer and three major NAC adducts were formed. One of these adducts was formed from 5-HT. The others were derived from TD and included 7-S-(N-acetylcysteinyl)tryptamine-4,5-dione). Both enzymes were essential for the generation of the products but XOD could be replaced by hydrogen peroxide. Superoxide, which was generated by XOD, was needed for the effective generation of TD through the incorporation of molecular oxygen into 5-HT.

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), which contains four cysteine residues was used as a model thiol protein. When exposed to TD, it lost thiols and quinone reactive moieties were formed on the protein.
This suggests that TD was covalently bound to the protein. Preliminary liquid chromatography mass spectrometry-based proteomic analysis indicated that one of the adducts formed when TD reacted with the protein involved the peptide containing Cys-244. We propose that during inflammation MPO will oxidize serotonin resulting in covalent modification of thiol residues on proteins.

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日本語要約

要するに、セロトニンの酸化反応を追いかけた。セロトニンの酸化方法として、酵素ミエロペルオキシダーゼを使い、ペプチドや酵素GAPDHに対する修飾反応を化学的、生化学的に調べた、と言う話しである。ニュージーランドでの仕事の内容なので、所属はニュージーランドで発表している。