Abstract:

 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 formenzyme-inhibitor complexes (EI and EI2), and the inhibition constants (Ki1 for EI and Ki2 for EI2) were 76.9 and 9.71 μmol·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.

Key words: Trifluoromethyl-containing 1,2,3-triazole, Mushroomtyrosinase, Monophenolase, Diphenolase, Reversible parabolic-competitive inhibition, Copper chelation