硫脲在酪氨酸酶催化中的抑制动力学

Inhibitory kinetics of thiourea on catalytic activity of mushroom tyrosinase

研究了硫脲对蘑菇酪氨酸酶活力的抑制效应。实验结果表明,硫脲与酪氨酸酶催化氧化产物醌反应,形成了无色的L-DOPA衍生物,从而阻断了多巴色素的形成。硫脲导致酪氨酸酶活力下降50%时的浓度(IC50)为1.37 mmol·L-1,在降低酶活的同时,硫脲能明显延长该酶的延滞时间,表现为不可逆反竞争性抑制。

Inhibitory effect of thiourea on the activity of mushroom tyrosinase was studied. Experimental results showed that thiourea reacted with the catalytic oxidation product of tyrosinase, quinone, and forming colorless L- DOPA conjugates, thereby the formation of DOPA melanin was blocked. Concentration of thiourea that resulting-in 50% of tyrosinase activity reduce （IC50） is 1.37 mmol· L^-1. Meanwhile thiourea can extend delay period of the tyrosinase. It demonstrated that the inhibition action of thiourea on mushroom tyrosinase is irreversible and uncompetitive.