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目的研究丹皮酚对酪氨酸酶活性的影响,为色素增加性皮肤病的治疗提供实验依据。方法选用酪氨酸酶催化氧化3,4-二羟基苯丙氨酸(L-Dopa)速率法体外测定酪氨酸酶活性。应用Lineweaver-Burk曲线推导丹皮酚对酪氨酸酶活性的抑制效应及Michaelis-Menten动力学。结果导致酪氨酸酶活力下降50%的丹皮酚浓度为0·60mmol·L-1。丹皮酚对游离酶的抑制常数(KI)和对酶底物络合物的抑制常数(KIS)分别为0·084和0·12mmol·L-1。结论丹皮酚是酪氨酸酶的混合型抑制剂,该抑制作用源于其能与酶中氨基结合生成席夫碱及能与活性中心的铜生成络合物。
Objective To study the effect of paeonol on tyrosinase activity and provide experimental basis for the treatment of hyperpigmented skin disease. Methods Tyrosinase catalyzed oxidation of 3,4-dihydroxyphenylalanine (L-Dopa) was used to determine tyrosinase activity in vitro. The inhibitory effect of paeonol on tyrosinase activity and Michaelis-Menten kinetics were deduced by using Lineweaver-Burk curve. As a result, the paeonol concentration at which tyrosinase activity decreased by 50% was 0·60 mmol·L-1. The inhibitory constant (KI) of paeonol to free enzymes and the inhibitory constant (KIS) to enzyme substrate complexes were 0·084 and 0.12 mmol·L-1, respectively. Conclusion Paeonol is a mixed inhibitor of tyrosinase. The inhibitory effect of paeonol is due to its ability to combine with the amino group of the enzyme to form Schiff base and copper complex with active center.