ヘムペロキシダースによるH2O2活性化の直接検査

Justine P Roth¹, Christopher J Cramer

¹Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA. jproth@jhu.edu

Journal of the American Chemical Society

|June 3, 2008

まとめ

この研究では,酸素同位体効果と計算方法を使用して,ヒースラディッシュ過酸化酵素 (HRP) が過酸化水素 (H2O2) を活性化する方法について調査し,反応機構に関する以前の仮定に異議を唱えました.

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
コンピューティング・ケミストリー

背景:

角根の過酸化酵素 (HRP) は,H2O2の活性化に不可欠です.
HRP触媒におけるO−O分裂ステップの可逆性は不明である.

研究の目的:

HRPによる酵素H2O2活性化のメカニズムを解明する.
酸素同位体効果を用いて,O−O分裂段階の可逆性を調査する.

主な方法:

酸素同位体の分割と計算方法の応用.
営業状況下でのH2O2消費に対する競争性酸素運動同位体効果 (18O KIE) の決定.
密度関数理論 (DFT) 移行状態と中間値のための計算.

主要な成果:

18O KIEを決定し,計算された同位体効果と比較した.
反応しないH2O2に18OラベルをHRP触媒で乱す証拠が観察されました.
この発見は,速度を制限するO−O異解の仮定に異議を唱える.

結論:

酸素同位体効果は,HRPによるH2O2活性化に関する新しい洞察を提供します.
この研究は,O-O割れ目のステップの速度制限に関する確立された見解に異議を唱える.
この研究は,ヘムペロキシダースによって触媒化されたH2O2の活性化に関する前例のない見解を提供します.

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