目的 研究氧化白藜蘆醇對酪氨酸酶抑制的作用機(jī)制。方法 將N-乙酰-L-酪氨酸代替酪氨酸作為底物，HPLC動態(tài)監(jiān)測氧化白藜蘆醇對酶催化生成多巴醌的影響；將對苯醌代替多巴醌，HPLC動態(tài)監(jiān)測其對非酶催化生成多巴色素的影響；分別以左旋酪氨酸和左旋多巴為底物，在pH 6.8的磷酸鹽緩沖體系反應(yīng)后測定475 nm吸光度值，研究氧化白藜蘆醇對酪氨酸酶催化反應(yīng)進(jìn)程和酶活性抑制的影響，計(jì)算酶的抑制動力學(xué)參數(shù)。結(jié)果 氧化白藜蘆醇對酪氨酸酶催化過程有抑制作用，對非酶催化過程有促進(jìn)作用。對酪氨酸酶單酚酶、二酚酶均有抑制作用，半抑制濃度（IC₅₀）分別為2.48 μmol/L、0.020 mmol/L。結(jié)論 氧化白藜蘆醇對酪氨酸酶的抑制類型為可逆抑制中的非競爭性抑制。

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.

國家自然科學(xué)基金資助項(xiàng)目（81602773）