Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8326819 | International Journal of Biological Macromolecules | 2018 | 29 Pages |
Abstract
The inhibitory effect of 2,4,5-T, 2,4-D, glyphosate and paraquat on the diphenolase activity of mushroom tyrosinase for oxidation of L-DOPA has been investigated by kinetic measurements, fluorescence spectroscopy and computational docking analysis. 2,4,5-T and 2,4-D inhibit the diphenolase activity of the enzyme following a competitive mechanism, while glyphosate is a mixed inhibitor according to Lineweaver-Burk kinetic analysis. The inhibitory activity follows the order glyphosate >2,4,5-Tâ¯>â¯2,4-D with IC50 values of 65, 90 and 106â¯Î¼M, respectively. Intrinsic tyrosinase fluorescence quenching and computational docking analysis suggest that 2,4,5-T and 2,4-D interact with the active site of the enzyme through hydrophobic interactions, while glyphosate also interacts with external residues of the active site of the enzyme by hydrogen bonding and hydrophilic interactions inducing conformational changes in the protein structure.
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Authors
Vibol Sok, Alex Fragoso,