含三氟甲基1,2,3-三氮唑衍生物对蘑菇酪氨酸酶活性的抑制动力学(英文)

Inhibitory Kinetics of a Trifluoromethyl-Containing 1,2,3-Triazole Derivative on Mushroom Tyrosinase Activity

研究表明,含三氟甲基1,2,3-三氮唑衍生物(TF-TZ)对蘑菇酪氨酸酶具有很强的抑制性:不仅抑制单酚酶活性,而且对二酚酶活性也是可逆性抑制,其半抑制浓度IC50分别为30.4和34.5μmol.L-1,并且单酚酶延滞时间随着TF-TZ浓度增加而延长.TF-TZ对二酚酶的抑制为抛物线型竞争性抑制,表明一分子的酶可以和两分子的TF-TZ相结合,从而形成两种酶-抑制剂复合物:EI和EI2,其抑制常数分别为76.9和9.71μmol.L-1.紫外-可见光谱表明,TF-TZ和酶相互作用后产成特征的"肩峰",说明TF-TZ能够作用于酶的活性中心.

In this study, we demonstrate that the trifluoromethyl-containing 1,2,3-triazole derivative （TF-TZ） inhibits mushroom tyrosinase. TF-TZ could inhibit the monophenolase and diphenolase activities and the inhibition is reversible. IC50 values of 30.4 and 34.5 μmol·L^-1 were estimated for the monophenolase activity and the diphenolase activity, respectively. TF-TZ could extend the lag period of the monophenolase activity. Kinetic analysis showed that parabolic-competitive inhibition of TF-TZ occurred on diphenolase. We proposed that two TF-TZ molecules combined with free tyrosinase to form enzyme-inhibitor complexes （Ei1 and Ei2）, and the inhibition constants （Ki1 for EI and Ki1 for Ei2） were 76.9 and 9.71μmol·L^-1, respectively. Moreover, the UV-Visible spectrum of a mixture of tyrosinase and TF- TZ exhibited a characteristic shoulder peak that could be assigned to chelation of TF-TZ to the active site.