Microenvironment engineering for tyrosinase immobilization: A combined molecular dynamics and experimental study on activity regulation

The catalytic performance of tyrosinase (TYR) is highly sensitive to its microenvironment, which poses challenges for its application in immobilized systems. Here, we systematically investigated the effects of different liquid-phase environments (organic solvents and ions) on TYR activity using molecular dynamics (MD) simulations and experimental assays. The results showed that TYR maintained its overall structural integrity in all tested environments, whereas its catalytic activity varied considerably. Global structural parameters ( RMSD , Rg , SASA ) reflected solvent-induced conformational changes and showed correlations with activity variations. Further analysis of local dynamics via RMSF , secondary structure ( DSSP ), and the coordination geometry of the Cu 2 + -histidine catalytic center suggested that increased flexibility near the catalytic pocket might be associated with activity loss. Based on these findings, solvents that minimize local flexibility changes and avoid direct interaction with the catalytic center are considered preferable for preserving activity. Moreover, we propose a carrier design consisting of an Fe 3 O 4 magnetic core coated with highly chlorinated polyvinyl chloride (CPVC), with Cu 2+ incorporated during coating to potentially help maintain active-site integrity. This work provides preliminary insights into the relationship between microenvironment, structural dynamics, and enzyme activity, and offers guidance for solvent selection and the design of immobilized enzyme systems.