The mixed-type inhibition of tyrosinase by puerarin: Kinetics and computer simulation

This paper uses inhibition kinetics, fluorescence spectroscopy, molecular docking, and molecular dynamics simulation to study how Puerarin (PUE) inhibits mushroom tyrosinase. Inhibition kinetics reveals that PUE inhibits tyrosinase in a reversible mixed-type manner with an IC 50 of 0.816 mmol/L and prefers binding to free tyrosinase. Fluorescence spectroscopy shows PUE binds spontaneously via static quenching with hydrophobic interactions as the main binding force and a single binding site. Synchronous and 3D fluorescence indicate PUE increases the microenvironment polarity of tyrosinase. Molecular docking confirms PUE can compete for the binding site and form a ternary complex. Molecular dynamics shows the tyrosinase/PUE complex is stable. In short, PUE inhibits tyrosinase by spontaneous binding in a reversible mixed-type manner. This characteristic provides theoretical support for its potential applications in the food industry, such as inhibiting browning and preserving fruits and vegetables, and in the cosmetics industry, such as serving as a natural whitening ingredient.