2023 Volume 81 Pages 3-19
Oxidation reactions utilizing reactive species generated on metal ions are important processes in biological reactions and various catalytic reactions. A typical example is dioxygen (O2) activation on iron and copper metal ions in the enzyme active sites. Although it appears to be a simple reaction, the diversity in structure, physicochemical properties, and reactivity of the generated reactive oxygen species makes it not so easy to control them. In metalloenzyme active centers, this is accomplished by skillfully exploiting the coordination geometry of the metal centers, electronic interactions with the coordinating atoms, and weak interactions in the secondary coordination sphere (hydrogen bonds, hydrophobic interactions, electrostatic interactions, etc.). Metalloenzymes are also known to cooperate with redox-active amino acid side chains (phenol group of tyrosine, thiol group of cysteine, indole group of tryptophan, etc.), coenzymes, or organic cofactors in the enzyme active site to perform the various enzymatic functions. Inspired by the essence of such metalloenzyme functions, we have been trying to create various metal-oxidizing active species and exploring their functions and catalytic applications. These studies are important not only for the elucidation of enzyme functions but also for the development of new catalysts. In this account, an overview of some of the research we have conducted is introduced.
