窒素酸塩とデオキシヘモグロビンとの反応で形成される新しいパラ磁性中間物質
Maria T Salgado1, Somasundaram Ramasamy, Antonio Tsuneshige
1Molecular Dynamics Section, National Institute on Aging, NIH, Baltimore, Maryland 21224, USA.
Journal of the American Chemical Society
|July 16, 2011
まとめ
研究者らは,ニートリートの還元で形成された新しいパラマグネット性ヘモグロビン種,SHb (SHb) ・II (II) NOを特定した. この中間物質は,安定したニートリート-ヘモグロビン相互作用を説明し,血管拡張のために酸化窒素 (NO) の放出に貢献します.
科学分野:
- バイオケミストリー バイオケミストリー
- 生理学 生理学とは
- 化学生物学 化学生物学とは
背景:
- 脱酸素化されたヘモグロビンによる窒素の減少は,赤血球によって誘発された血管拡張と関連しています.
- このプロセスの正確なメカニズムと反応中間物質の安定性は不明である.
研究 の 目的:
- 脱酸素ヘモグロビンによるニートリートの還元過程で,提案された電子伝送中間物質,SHb (II) NOの形成と性質を調査する.
- 窒素酸化物 (NO) の生物活性におけるニートリート-ヘモグロビン反応中介物質の安定性とその役割の背後にあるメカニズムを解明する.
主な方法:
- 電子パラマグネティック共振 (EPR) スペクトロスコピーは,パラマグネティックな種を検出するために使用されました.
- 実験では,β-93チオール群をN-エチル-マレイミドでブロックし,カルボキシペプチダゼ-Aを使用してR-四極形状を安定させました.
主要な成果:
- EPR分析は,ヘム結合NOとチール基の両方からの信号によって特徴づけられる,SHb (II) NOの形成を確認した.
- この種は,ハイブリッド中間物質 (Hb(II) NO(+) Hb(III) NO) とバランス状態で存在し,さらにNO結合を安定させます.
- 低温インキュベーション (−20°C) は均衡をシフトさせ,提案されたメカニズムを支持した.
結論:
- 新しいNO-ヘモグロビンパラマグネティック種, ·SHb(II) NOが特定されました.
- この中間物質は,反応産物の安定性と,窒素還元過程で生物活性なNOの蓄積を説明する.
- この発見は,既知の血管拡張剤であるS-ニトロシル化ヘモグロビン (SNOHb) 形成の経路を提供する.
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