Nanobiotechnology & Bioanalysis Group, Departament d'Enginyeria Química, Universitat Rovira i Virgili, Avinguda Països Catalans 26, 43007 Tarragona, Spain.
Nanobiotechnology & Bioanalysis Group, Departament d'Enginyeria Química, Universitat Rovira i Virgili, Avinguda Països Catalans 26, 43007 Tarragona, Spain.
Int J Biol Macromol. 2018 Oct 15;118(Pt A):427-434. doi: 10.1016/j.ijbiomac.2018.06.098. Epub 2018 Jun 23.
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-T > 2,4-D with IC values of 65, 90 and 106 μM, 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.
通过动力学测量、荧光光谱和计算对接分析，研究了 2,4,5-T、2,4-D、草甘膦和百草枯对蘑菇酪氨酸酶氧化 L-DOPA 的二酚酶活性的抑制作用。动力学分析表明，2,4,5-T 和 2,4-D 按竞争性机制抑制酶的二酚酶活性，而草甘膦是根据 Lineweaver-Burk 动力学分析的混合抑制剂。抑制活性的顺序为草甘膦>2,4,5-T>2,4-D，IC 值分别为 65、90 和 106 μM。本构酪氨酸酶荧光猝灭和计算对接分析表明，2,4,5-T 和 2,4-D 通过疏水相互作用与酶的活性位点相互作用，而草甘膦还通过氢键和亲水相互作用与酶的活性位点的外部残基相互作用，诱导蛋白质结构的构象变化。
