Cofactor-free organic nanozyme with assembly-induced catalysis and light-regulated activity

Organic nanozymes that mimic cofactor-free enzymes avoid the use of metal ions and other cofactors, and show great advantages in the field of biomimetic catalysis. The assembly of organics such as peptides is usually necessary for their catalysis and is also a major challenge for organic nanozymes. Here we constructed cofactor free organic nanozyme by self-assembly of cyclodextrins modified gold nanoparticle and azobenzene modified peptide chain through host-guest interaction. At room temperature, free peptide chain has negligible catalytic activity. Organic nanozyme reduces the activation energy and increases the reaction rate of hydrolysis of 4-nitro phenyl acetate. The catalysis of organic nanozyme derives from the ordered assembly of peptide chains on the surface of support and the deprotonation of the imidazole groups of neighboring histidines that facilitates the splitting of a proton from water, and thus promotes the nucleophilic attack on the incoming substrate. Photoisomerization of azobenzene group leads to the assembly and disassembly of nanozyme, causing the change of catalytic activity. These findings may contribute to the design of advanced biomimetic catalysts and provide a model for cofactor-free nanozymes.