羊栖菜多糖提取物对酪氨酸酶的抑制作用研究
Study on inhibition effect of Sargassum fusiforme polysaccharide extracts on activity of tyrosinase
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摘要: 目的:研究羊栖菜多糖提取物对酪氨酸酶活性的抑制作用和对结构的影响。方法:提取羊栖菜多糖并测定含量,以L-DOPA为底物,在475nm处测定吸光度,观察羊栖菜多糖提取物对酪氨酸酶二酚酶活力的影响;测定羊栖菜多糖作用下酪氨酸酶内源荧光和ANS结合的荧光的变化,以判断对酶结构的影响情况。结果:羊栖菜多糖提取物对蘑菇酪氨酸酶有明显的抑制作用,可以导致酪氨酸酶的二酚酶活力下降。羊栖菜多糖使二酚酶活力下降一半时的抑制剂浓度（IC50）为（2.16±0.37）mg/mL。羊栖菜多糖对酪氨酸酶的抑制作用是一个可逆过程,抑制类型为混合型抑制。通过动力学分析,测得羊栖菜多糖对酪氨酸酶的抑制常数（Ki）为（4.34±0.56）mg/mL。荧光测定结果表明,羊栖菜多糖的结合引起酪氨酸酶三级结构的明显改变。结论:羊栖菜多糖与酪氨酸酶的结合引起酶结构的变化,并以混合抑制的方式可逆抑制酪氨酸酶的二酚酶活性。本实验为进一步研究和设计新型酪氨酸酶抑制剂奠定科学基础。Abstract: Objective:To study the inhibitory effect of the Sargassum fusiforme polysaccharide (SFPS) extracts on the activity of tyrosinase for diphenolase.Methods:Extract SFPS and measure the content of polysaccharide.To investigate the effect of SFPS extracts on the diphenolase activity, the absorbance of the solution containing several concentrations of the SFPS extracts was measured at 475nm, using the L-DOPA as the substrate.Endogenous fluorescence and ANS-binding fluorescence of tyrosinase were tested with different concentrations of SFPS.Results:SFPS could obviously inhibit the activity of tyrosinase for diphenolsae.The inhibitory concentration leading to 50% activity lost (IC 50) was estimated to be (2.16±0.37) mg/mL.The results showed that SFPS was a reversible inhibitor of mushroom tyrosinase.Lineweaver-Burk plots indicated that SFPS was a mixed-type inhibitor, and its inhibition constant Ki were (4.34±0.56) mg/mL.Endogenous fluorescence and ANSbinding fluorescence test of tyrosinase indicated that SFPS combined with the tyrosinase caused significant changes in the structure.Conclusion:SFPS combined with the tyrosinase caused significant changes in the structure and reversible inhibited the activity of tyrosinase for diphenolsae in a mixed-type manner.Together these results provided a scientific basis for the design and development of new inhibitors in the future.
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