Abstract:To investigate the inhibitory effect of Mangiferin (Man) on Tyrosinase (TYR), this study determined the type of inhibition through enzyme kinetics and explored the mechanism and structural impact of Man on TYR through multispectral analysis. The results showed that the half inhibitory concentration (IC50) of Man on TYR was (35.04 ± 1.14) μmol/L, and the concentration of Man when 90% inhibition was achieved (IC90) was (86.53 ± 2.37) μmol/L. Enzyme kinetics experiments showed that Man is a mixed inhibition type that combines competitive and non-competitive inhibition, and has a single binding site with TYR, tending to bind to free enzymes. Man exhibits copper ion chelation, which also suggested the possibility of a competitive inhibition type. Fluorescence spectroscopy showed that Man induced static quenching of TYR, resulting in the formation of TYRMan complexes. This result was confirmed by UV spectroscopy and F?觟rster energy transfer theory. The binding constant is on the order of 104 L/mol, the binding force is moderate, and the number of binding sites equals 1. Thermodynamic parameters indicated that the main driving force for the binding of Man and TYR is hydrophobic interaction. Based on the results of infrared spectroscopy, hydrophobicity experiments, and differential scanning calorimetry, it is speculated that Man mainly drives the folding of TYR through hydrophobic interactions, reducing the stability of TYR and causing exposure of hydrophobic regions or loosening of protein structure, making it easy for ANS to enter. Conclusion: Man has strong inhibitory ability and binding affinity towards TYR, which may hinder the binding of substrates to TYR. In addition, during the binding process, Man will alter the conformation of the enzyme, reduce the stability of TYR, and make it more prone to denaturation.