目的 研究氧化白藜芦醇对酪氨酸酶抑制的作用机制。方法 将N-乙酰-L-酪氨酸代替酪氨酸作为底物，HPLC动态监测氧化白藜芦醇对酶催化生成多巴醌的影响；将对苯醌代替多巴醌，HPLC动态监测其对非酶催化生成多巴色素的影响；分别以左旋酪氨酸和左旋多巴为底物，在pH 6.8的磷酸盐缓冲体系反应后测定475 nm吸光度值，研究氧化白藜芦醇对酪氨酸酶催化反应进程和酶活性抑制的影响，计算酶的抑制动力学参数。结果 氧化白藜芦醇对酪氨酸酶催化过程有抑制作用，对非酶催化过程有促进作用。对酪氨酸酶单酚酶、二酚酶均有抑制作用，半抑制浓度（IC₅₀）分别为2.48 μmol/L、0.020 mmol/L。结论 氧化白藜芦醇对酪氨酸酶的抑制类型为可逆抑制中的非竞争性抑制。

Objective To explore the inhibitory mechanism of oxyresveratrol on tyrosinase. Methods Using N-acetyl-L-tyrosine as a substrate instead of tyrosinase to block nonenzymatic process, the effect of oxyresveratrol on tyrosinase involving dopaquinone enzyme catalyzed reaction process was studied with HPLC dynamic monitoring analysis. Using p-benzoquinone as a substrate instead of dopaquinone, the effect of oxyresveratrol on the tyrosinase involving dopachrome nonenzyme catalyzed reaction process was studied with HPLC dynamic monitoring analysis. Using L-tyrosine and L-dopa as substrate, absorbance was measured at 475 nm after reacted in phosphate buffer solution (pH 6.8). The effect of oxyresveratrol on the catalytic reaction of tyrosinase and inhibition of enzyme activity were studied, and kinetic parameters of enzyme inhibition were calculated. Results Oxyresveratrol can inhibit the catalytic process of tyrosinase. Oxyresveratrol could efficiently inhibit monophenolase and diphenolase activity of tyrosinase, and their half inhibitory concentrations were 2.48 μmol/L and 0.020 mmol/L. Conclusion The inhibitory type of oxyresveratrol on tyrosinase is a non competitive inhibition in reversible inhibition.

国家自然科学基金资助项目（81602773）