Thermal Investigation of P-Phenylene-Bis and Phenyl Dithiocarbamate Binding to Mushroom Tyrosinase

Abstract

The binding properties and structural changes of mushroom tyrosinase enzyme, MT, due to its interaction with phenyl dithiocarbamate (I) and p-phenylene-bis dithiocarbamate (II) were investigated at 27 and 37°C in phosphate buffer (10 mmol.L-1) at pH=6.8 by isothermal titration calorimetric (ITC). Thermodynamic analysis indicated that predominant mode of interaction was hydrophobic in binding of I to MT, meanwhile the binding of II to MT essentially depends on electrostatic interactions. It seems thatII is a more potent MT inhibitor due to its two charged head groups able to chelate copper ions in the enzyme active site. It was concluded that MT has two distinct sites for p-phenylene-bis and phenyl dithiocarbamate.