Degradation of chemicals by reactive radicals produced by cellobiose dehydrogenase from Phanerochaete chrysosporium.
Phanerochaete chrysosporium, grown on cellulose, produced a cellobiose-dependent dehydrogenase which reduced both ferric iron and molecular oxygen, resulting in the generation of the hydroxyl radical. The hydroxyl radical was detected in reaction mixtures with and without the addition of exogenous H2O2. The purified reductase and the fungus grown under nonligninolytic conditions that promote the production of the reductase were able to depolymerize an insoluble polyacrylate polymer. When oxalate, a secondary metabolite of P. chrysosporium, was used as the iron chelator, it was oxidized by the hydroxyl radical to form the carboxylate anion radical, a strong reductant. Under these reductive conditions, the enzyme was shown to catalyze the reduction of bromotrichloromethane to the trichloromethyl radical. We propose that these oxidative and reductive mechanisms may contribute to the degradation of a wide range of environmental pollutants by fungi which produce this enzyme.
Cameron
M D
MD
Biotechnology Center, Utah State University, Logan, Utah, 84322-4705, USA.
Aust
S D
SD
D000180:Acrylic Resins / Q000378:metabolism; D000838:Anions / Q000378:metabolism; D001673:Biodegradation, Environmental; D001975:Bromotrichloromethane / Q000378:metabolism; D002237:Carbohydrate Dehydrogenases / Q000378:metabolism*; D002251:Carbon Tetrachloride / Q000031:analogs & derivatives / Q000378:metabolism; D002264:Carboxylic Acids / Q000378:metabolism; D002475:Cellobiose / Q000378:metabolism; D002482:Cellulose / Q000378:metabolism; D005609:Free Radicals / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism; D017665:Hydroxyl Radical / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D007502:Iron Chelating Agents / Q000378:metabolism; D019815:Oxalic Acid / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D020075:Phanerochaete / Q000201:enzymology* / Q000254:growth & development; D019163:Reducing Agents / Q000378:metabolism; D012995:Solubility; D019097:Spin Trapping
D000180:Acrylic Resins; D000838:Anions; D002264:Carboxylic Acids; C045076:Fenton's reagent; D005609:Free Radicals; D007502:Iron Chelating Agents; D019163:Reducing Agents; D002475:Cellobiose; C025280:trichloromethyl free radical; D017665:Hydroxyl Radical; C006903:carbopol 940; D002482:Cellulose; D019815:Oxalic Acid; D006861:Hydrogen Peroxide; D002251:Carbon Tetrachloride; D007501:Iron; D002237:Carbohydrate Dehydrogenases; C019859:cellobiose-quinone oxidoreductase; D001975:Bromotrichloromethane; D010100:Oxygen