title: Cytochemical discrimination between catalases and peroxidases using diaminobenzidine.
abstract: The influence on diaminobenzidine staining of four variables: prefixation in aldehyde, temperature and pH of incubation, and H2O2 concentration, was investigated in catalase-, as well as in peroxydase-containing material. Catalase from five different sources and five types of peroxidase were examined. It is concluded: (a) when cells are incubated without prior fixation, in a DAB medium at room temperature and pH 7.3 with 0.003% H2O2, peroxidases produce a visible cytochemical stain, while catalases do not; (b) the cytochemical reaction elicited by catalases is stimulated by prior aldehyde fixation in specified conditions, and incubation at 45 degrees C and pH 9.7 with 0.06% H2O2; (c) under the latter circumstances several peroxidases also stain. Ultrastructural preservation is satisfactory in tissues incubated prior to fixation.
mesh_terms: D000611:Aminobiphenyl Compounds; D000818:Animals; D001560:Benzidines; D002021:Buffers; D002374:Catalase / Q000032:analysis*; D003959:Diamines; D005260:Female; D005629:Frozen Sections; D005976:Glutaral; D006651:Histocytochemistry; D006801:Humans; D006861:Hydrogen Peroxide; D006863:Hydrogen-Ion Concentration; D008297:Male; D051379:Mice; D008830:Microbodies / Q000201:enzymology; D010544:Peroxidases / Q000032:analysis*; D051381:Rats; D013696:Temperature
chemical_list: D000611:Aminobiphenyl Compounds; D001560:Benzidines; D002021:Buffers; D003959:Diamines; D006861:Hydrogen Peroxide; D010544:Peroxidases; D002374:Catalase; D005976:Glutaral