title: L-Dopa peroxidase activity of human erythrocyte catalase.
abstract: The human red cell hemolysate was found to have 3-(3',4'-dihydroxphenyl)-L-alanine (L-dopa) peroxidase activity. During the purification of glutathione peroxidase and catalase by ammonium sulfate precipitation, ion exchange chromatography. Sephadex gel filtration, and preparative polyacrylamide disc electrophoresis, the L-dopa peroxidase activity was found to be associated with catalase. Both sodium azide, 8 mM, and 3-amino-1,2,4-triazole, 50 mM, besides inhibiting catalase, inhibited the L-dopa peroxidase activity in each fraction. Ethylenediamine tetraacetic acid (EDTA), 4 mM, had no effect on catalase or L-dopa peroxidase activity, indicating that the oxidation of L-dopa is not a nonenzymatic process mediated by metal ions. Although the electrophoretic mobility of catalase, L-dopa peroxidase, and glutathione peroxidase are similar, a homogeneous preparation of glutathione peroxidase was free of L-dopa peroxidase activity. L-Dopa peroxidase in human red cells was co-purified with catalase.
mesh_terms: D001386:Azides / Q000494:pharmacology; D002374:Catalase / Q000097:blood*; D002850:Chromatography, Gel; D004492:Edetic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000201:enzymology*; D006358:Hot Temperature; D006801:Humans; D007980:Levodopa; D010544:Peroxidases / Q000097:blood*
chemical_list: D001386:Azides; D007980:Levodopa; D004492:Edetic Acid; C020090:L-dopa peroxidase; D010544:Peroxidases; D002374:Catalase