合成ヘム-チオラート複合体によって触媒化された酸化反応における複数の活性中間物質は,サイトクロームp450に関連しています

Noriyuki Suzuki¹, Tsunehiko Higuchi, Tetsuo Nagano

¹Contribution from the Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo, Bunkyo-ku, Japan.

Journal of the American Chemical Society

|August 9, 2002

まとめ

合成のヘム-チオラート複合体は酸化反応を触媒化する. 基板と酸化物質の相互作用は,酸素-酸素結合の割れ前に発生し,酸素原子移転におけるヘム-チオラートメカニズムに関する以前の仮定に異議を唱える.

科学分野:

バイオ・オーガニック化学バイオ・オーガニック化学
有機化学オーガニック・ケミストリー
カタリシスカタリシスカタリシス

背景:

ヘム-チオラート複合体は,生物学的酸化反応において極めて重要です.
酸素原子移転のメカニズムを理解することは,触媒設計に不可欠です.
以前のモデルでは,ヘムチオラートが主にO-O結合の分裂を促進することを示唆していた.

研究の目的:

ヘム・チオラートによる催化酸素原子移転における中間物質の役割を調査する.
反応機構における一連の出来事を決定する.
基板と酸化物質の相互作用を解明する.

主な方法:

様々な基質でペロキシフェニルアセティック酸 (PPAA) の分解を研究した.
代替ペロキシベンゾ酸を用いて,サイクロオクタンとサイクロオクテンの競争性酸化を行った.
活性中間物質を特定するために,18O-インコーポレーション研究を利用した.

主要な成果:

PPAA O-O結合割れモードは基板の反応性に依存し,簡単に酸化される基板による異解性割れを好みました.
アルケンの水酸化とアルケンのエポキシデーションの比率は,ペロキシベンゾ酸酸化剤のパラ置換物によって変化した.
(18) O-ラベル付けの結果は,提案された反応機構を支持した.

結論:

基板と酸化物質は,酸素原子の移転中に相互作用します.
酸化は,O−O結合の割れ前に発生し,ヘム・チオラート触媒を使用してもそうである.
ヘムチオラートは,O-O結合の分裂を促すだけでなく,そのメカニズムはより複雑です.

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