ヒトP450におけるCYP17A1媒介によるアンドロゲン形成における溶媒同位体の運動効果:反応性ペロキソアニオン中間物質の証拠
Michael C Gregory1, Ilia G Denisov, Yelena V Grinkova
1Department of Biochemistry, University of Illinois at Urbana-Champaign , Urbana, Illinois 61801, United States.
Journal of the American Chemical Society
|October 29, 2013
まとめ
研究者らは,男性ホルモンデヒドロエピアンドロステロンの形成のメカニズムを研究した. 大量の逆同位体効果は,シトクロームP450CYP17A1.1.のC-C結合分裂活性における鉄結合フェリックペロキオアニオン中間物質を示唆している.
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
- ステロイド生成 (ステロイドゲネシス)
背景:
- ヒトのステロイドホルモンのバイオシンセシスは,コレステロールの複雑な変換を伴う.
- サイトクロームP450酵素,特にCYP17A1は,ステロイド生成に不可欠です.
- CYP17A1は,デヒドロエピアンドロステロンの形成における水酸化とC-C結合の分裂の両方を媒介する.
研究 の 目的:
- P450CYP17A1.1.のC-C結合分裂 (ライアゼ) 活動のメカニズムを調査する.
- C17-C20結合割れに関与する反応性中間物質を調査する.
主な方法:
- ナノディスクに組み込まれたCYP17A1.1.の動力同位体効果の研究
- 安定状態の売上高率の分析.
主要な成果:
- ヒドロキシラーゼの活性について,小さな陽性運動同位体効果 (~1.3) が観察されました.
- 大量の逆運動同位体効果 (~0.39) がC−C結合分裂活動で測定された.
結論:
- この結果は,CYP17A1のライアゼ機能に対する新しい反応機構を示唆している.
- この発見は,C−C結合の裂解における反応性中間体として,鉄に結合したフェリックペロキオアニオンを強く示している.
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