Superactivity of Bimetallic CuFeO₂ Submicron Particles towards Selective Proteolysis, Depending on their Surface...

Nano bimetallic oxides as nanoproteases have the great advantages in the heterogeneous hydrolysis of proteins. Here, we report that bimetallic delafossite CuFeO₂ submicron particles (CuFeO₂ SMPs) display a high protease activity towards selective cleavage of peptide bond involving hydrophobic residue at 25 °C. CuFeO₂ SMPs have excellent regeneration performance with high structural stability. The strong Lewis acidity of Fe³⁺ and the strong nucleophilicity of Cu⁺ bound hydroxyl groups are both necessary for the high protease activity of CuFeO₂ SMPs. Low-valent metal ion has a great advantage in that low-valent Cu⁺ bound hydroxyl has strong nucleophilicity, resulting in promotion of protein hydrolysis via high-efficient bimetallic catalysis. This study provides evidence that the protease activity of CuFeO₂ SMPs depends on metal ion-bound hydroxyls on their surface. Our findings highlight that the valence of metal ions in artificial protease and their surface hydroxyls are two important factors that determine their catalytic efficiency.