非酵素トランスアミネーションにおける金属-ピリドクサルの協力性
Quentin Dherbassy1, Robert J Mayer1, Kamila B Muchowska1
1Université de Strasbourg, CNRS, ISIS & icFRC, 8 Allée Gaspard Monge, 67000 Strasbourg, France.
Journal of the American Chemical Society
|June 6, 2023
まとめ
鉄やアルミニウムのような金属イオンは,トランスアミネーション反応におけるコエンザイムであるピリドクスアル (PL) の触媒活性を著しく高めます. これは,酵素が進化する前に,共酵素が触媒的に機能し,初期の生命化学の洞察を提供していたことを示唆している.
科学分野:
- 生命 研究 の 起源
- 生物化学
- キャタリシス
背景:
- 同酵素は酵素反応の30%以上において重要であり,酵素より先行する可能性があります.
- コエンザイムが有機触媒として,特にプレバイオティック化学における触媒的可能性は,まだ十分に理解されていない.
- メタルイオンは,酵素がなくても,代謝反応の触媒として知られています.
研究 の 目的:
- 生命の起源に関連する条件下で,メタルイオンの触媒作用を調査する.
- 過剰な金属イオン (Fe,Al) とピリドクサール (PL) がトランスアミネーション反応に作用するシナージ効果を探求する.
主な方法:
- Fe3+とAl3+イオンの存在下で,ピリドクサール (PL) とピリドクサールリン酸 (PLP) によって触媒化されたトランスアミネーション反応を研究した.
- 初期の地球 (20-75°C,pH 5-7.5) を模倣した条件下で実験を行った.
- 反応経路の解明のために実験的および理論的メカニズム研究を行いました.
主要な成果:
- Fe3+- PLおよびAl3+- PL複合体は,PLまたは金属イオン単独と比較して,トランスアミネーション触媒を大幅に強化しました.
- Al3+- PLの触媒は,軽い条件下では,PL単独よりも1000倍以上速い.
- PLへの金属調整は反応機構を変化させ,イミンの中間水解を遅らせた.
結論:
- ピリドクサルの誘導体は,金属イオンと併用して,酵素の進化を先導する重要な触媒活性を有していた可能性がある.
- この発見は,プレバイオティック環境における初期の生化学反応のあり得るメカニズムを提供する.
- 同酵素は生命の出現に 重要な触媒的役割を果たしたのかもしれません
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