Minimalistic Copper Amino Acid Assemblies as Laccase Mimics for Oxidative Pollutant Removal

Abstract Laccase, a typical multicopper oxidase, catalyzes the oxidation of phenolic and aromatic compounds using molecular oxygen as the terminal electron acceptor, but its practical application is often hindered by high production cost, complicated preparation procedures, and limited operational stability. Herein, we report a simple yet effective strategy to construct laccase-mimicking artificial enzymes through the coordination of Cu2+ with acidic amino acids as minimal biomolecular building blocks. By varying ligand structure and chirality, a series of copper-based amino-acid nanozymes were obtained, including CuAspL, CuAspD, CuGluL, and CuGluD. Among the four assemblies, CuGluL exhibited the highest apparent laccase-like activity in the 2,4-DCP/4-AAP model reaction under identical catalyst mass-loading conditions. Structural characterization revealed ligand-dependent differences in assembly morphology and copper valence-state distribution, which coincided with differences in apparent catalytic activity among the four assemblies. In addition to appreciable catalytic activity, the artificial enzymes showed excellent stability over a broad temperature range and under near-neutral to weakly alkaline conditions. They also demonstrated promising applicability in the oxidative degradation of representative endocrine-disrupting pollutants, including triclosan and diclofenac. This work provides a low-cost and scalable route for constructing laccase-mimicking catalysts from simple amino-acid-metal coordination and offers insights into the design of robust biomimetic catalysts for environmental applications.