The inhibitory effect of ethylenediamine on mushroom tyrosinase

The inhibitory effect of ethylenediamine on both activities of mushroom tyrosinase (MT) at 20 degrees 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 (K-i) of 0.18 +/- 0.05 and 0.14 +/- 0.01 mu M 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. (C) 2012 Elsevier B.V. All rights reserved.