Purification and properties of parathion-degrading enzyme from Aspergillus niger Y-8.
A parathion-degrading enzyme was purified from Aspergillus niger Y-8 cells, cultured at 30°C for 5 days. The enzyme was a monomer protein with a molecular weight of 42 000 Da. The optimal conditions for enzyme activity were pH 7.5 and 50°C. The enzyme was stable over the range of pH 6-9 and below 40°C. Activity was inhibited by SDS, Hg2+, Ag+, and Fe3+. The enzyme was capable of degrading other organophosphorus pesticides, such as methylparathion [parathion-methyl] and dichlorvos. The Km and Vmax values of the enzyme were determined.