Xiao-Xin Chen, Jian Zhang, Wei-Ming Chai, Hui-Ling Feng,Zhi-Hao Xiang, Dong-Yan Shen, Qing-Xi Chen.International Journal of Biological Macromolecules, 2013. 62: 726-733.

In the present work, we investigated the inhibitory effects of amoxicillin, a bacteriolytic -lactam antibiotic drug, on the rate of monophenol hydroxylation and o-diphenol oxidation catalyzed by mushroomtyrosinase. The results showed that amoxicillin could inhibit both monophenolase and diphenolase activities. For monophenolase activity, the inhibition on reaction rate was dose-dependent, while the influenceon lag period was not obvious. For diphenolase activity, amoxicillin was found to be a reversible inhibitor,with an IC50value of 9.0±1.8 mM. Kinetics analysis showed that amoxicillin was a mixed type inhibitorof the enzyme with KIand KISvalues of 8.30 mM and 44.79 mM, respectively. Further, the molecularmechanism underlying the inhibition of tyrosinse by amoxicillin was investigated by means of fluorescence quenching and molecular docking techniques. The results showed that amoxicillin could formstatic interaction with the catalytic pocket of the enzyme through the interaction of amoxicillin with thedicopper irons and amino acid residues in the enzyme active center. Our results contributed to the usageof amoxicillin as a potential tyrosinase inhibitor in the field of medicinal industry and could also provideguidance in the design of novel tyrosinase inhibitors.