The inhibitory effect of ethylenediamine on mushroom tyrosinase

The inhibitory effect of ethylenediamine on both activities of mushroom tyrosinase (MT) at 20 °C in a 10 mM phosphate buffer solution (pH 6.8), was studied. l-DOPA and l-tyrosine were used as substrates of catecholase and cresolase activities, respectively. The results showed that ethylenediamine competitively inhibits both activities of the enzyme with inhibition constants (Ki) of 0.18 ± 0.05 and 0.14 ± 0.01 μM for catecholase and cresolase respectively, which are lower than the reported values for other MT inhibitors. For further insight a docking study between tyrosinase and ethylenediamine was performed. The docking simulation showed that ethylenediamine binds in the active site of the enzyme near the Cu atoms and makes 3 hydrogen bonds with two histidine residues of active site.