脂肪酸アルファ-オキシゲナゼにおけるタンパク質ラジカル媒介による核トンネリングの証拠
Ankur Gupta1, Arnab Mukherjee, Kenji Matsui
1Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore Maryland 21218, USA.
Journal of the American Chemical Society
|August 6, 2008
まとめ
米アルファオキシゲナーゼ (RalphaO) はチロシル基を脂肪酸酸化に利用し,変異研究と大きなデウテリウム同位体効果によって確認されています. この酵素は,その根幹機構において,重要な量子トンネリングを披露している.
科学分野:
- バイオケミストリー バイオケミストリー
- 酵素学 酵素学とは
- 量子生物学とは,量子生物学である.
背景:
- 米のアルファオキシゲナーゼ (RalphaO) は,脂肪酸のカルファ-H結合にO2の挿入を触媒化する.
- そのメカニズムは,サイクロオキシゲネーゼと類似したチロシル基を伴うと推測されています.
研究 の 目的:
- ライスアルファオキシゲナーゼ (RalphaO) の触媒機構を調査する.
- RalphaO機能に触媒性チロシルラジカルが関与していることを確認するために.
- 酵素触媒における量子効果を調査する.
主な方法:
- サイト・ダイレクト・ミュータゲネシス (Tyr379Phe変異体).
- 運動学的研究.
- スペクトル分析. スペクトル分析.
- デウテリウムの運動同位体効果の測定.
主要な成果:
- 証拠は,不可逆的な水素原子抽象化メカニズムを支持しています.
- タイロシル基 (Tyr*) の触媒作用が確認された.
- 温度に依存しない非常に大きなデュテリウム運動同位体効果 (~50) が観察されました.
結論:
- 米のアルファオキシゲナーゼ (RalphaO) は,チロシル基を触媒として使用します.
- 広範囲にわたる核トンネリングは,酵素の反応機構に大きく貢献する.
- RalphaOは,アミノ酸根酵素における量子効果の新たな例を示しています.
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