Optimization of Fe₃O₄ nanozyme activity via single amino acid modification mimicking an enzyme active site

Abstract

The Fe₃O₄ nanozyme was the first reported nanoparticle with intrinsic peroxidase-like activity and has been widely used in biomedicine. To optimize its catalytic activity, we introduced histidine residues onto the Fe₃O₄ nanoparticle surface in order to mimic the enzymatic microenvironment of natural peroxidase enzymes. Our results show that modification with a single amino acid could more than ten-fold improve the apparent affinity (K_M) of the Fe₃O₄ nanozyme for the substrate H₂O₂ and enhanced its catalytic efficiency (k_cat/K_M) up to twenty fold. Thus we not only optimized the activity of the Fe₃O₄ nanozyme, but also provide a new rationale for improving the efficiency of nanomaterial-based catalysts by utilizing strategies observed in nature.