茶多酚对酪氨酸酶的抑制作用及分子机制研究

Inhibitory effect of tea polyphenols on tyrosinase and its molecular mechanism

中文关键词:  茶多酚，酪氨酸酶，抑制作用，空间结构，分子对接

英文关键词:tea polyphenols  tyrosinase  inhibitory effect  spatial structure  molecular docking

中文摘要:

      目的 研究茶多酚对酪氨酸酶的抑制作用及分子机制。方法 通过生化分析法, 测定茶多酚对酪氨酸酶的抑制作用并分析其抑制动力学; 采用荧光光谱、圆二色谱和分子模拟技术, 剖析茶多酚对酪氨酸酶抑制作用的分子机制。结果 茶多酚对酪氨酸酶有良好的抑制作用, 对其单酚和多酚活性的半数抑制浓度分别为0.66 mg/mL和1.76 mg/mL, 为竞争性抑制; 茶多酚可使酪氨酸酶出现明显的荧光淬灭和最大发射波长红移, 并使酪氨酸酶二级结构中的α-螺旋结构显著增加, β-折叠、β-转角和无规则卷曲结构显著减少, 显著改变酪氨酸酶的三级和二级结构。结论 茶多酚主要通过氢键和静电相互作用与酪氨酸酶进行结合, 从而改变酪氨酸酶的空间结构并阻碍其与底物进行结合, 进而抑制酪氨酸酶的活性。

英文摘要:

      Objective To investigate the inhibitory effect and molecular mechanism of tea polyphenols on tyrosinase. Methods The inhibitory effect of tea polyphenols on tyrosinase was determined by biochemical analysis and its inhibition kinetics were analyzed. Fluorescence spectroscopy, circular dichroism and molecular simulation techniques were used to analyze the inhibitory effect and molecular mechanism of tea polyphenols on tyrosinase. Results Tea polyphenols exhibited a good inhibitory effect on tyrosinase, and the half inhibitory concentrations of their monophenolic and polyphenolic activities were 0.66 mg/mL and 1.76 mg/mL, which was the competitive inhibition. Tea polyphenols could cause obvious fluorescence quenching and maximum emission wavelength redshift of tyrosinase. Meanwhile, tea polyphenols increased the α-helix structure and reduced β-folding, β-angle, random coil structure of tyrosinase significantly, which indicated that tea polyphenols significantly changed the tertiary and secondary structures of tyrosinase. Conclusion Tea polyphenols interacted with tyrosinase mainly by hydrogen bonds and electrostatic interactions, so as to change the spatial structure of tyrosinase and prevent its binding to the substrate, thereby inhibiting the activity of tyrosinase.