CuCoO₂ Nanoparticles as a Nanoprotease for Selective Proteolysis with High Efficiency at Room Temperature

Many nanoproteases contain tetravalent metal ions and catalyze peptide-bond hydrolysis only at high temperature (60 °C). Here, we report a new and effective strategy to explore nanoproteases from nanoparticles containing low valent metal ions. We found that flower-like CuCoO₂ nanoparticles (CuCoO₂ NPs) containing low valent Cu⁺ possessed excellent catalytic activity towards selective cleavage of peptide bonds with hydrophobic residues in bovine serum albumin (BSA) at room temperature. CuCoO₂ NPs exhibited excellent stability and had great reusability. CuCoO₂ NPs also hydrolyzed heat-denatured and surfactant-denatured BSA. Mechanism analysis revealed that the high Lewis acidity of Co³⁺ and the low valence of Cu⁺ were both essential for the high protease activity of CuCoO₂ NPs. The flower-like structure of CuCoO₂ NPs and the strong nucleophilicity of Cu⁺ -bound hydroxyl endow them with excellent catalytic performance. The findings open a new way for the design and discovery of high-efficiency nanoproteases.