MITOCHONDRIAL OXIDATION OF 3, 3′-DIAMINOBENZIDINE AT VARIOUS pH VALUES

Abstract

Osmium black reaction products from 3,3''-diaminobenzidine (DAB) oxidation via rat kidney mitochondrial cytochrome c oxidase were studied relative to a wide range of incubating pH values and with different incubating times. The reaction products were localized within the mitochondrial cristae and outer compartments. The greatest amount of reaction products appeared at pH 8.0-8.4. The best membrane-localized reaction with fine products occurred at pH 7.2-7.4. Reducing the incubating time resulted in more precisely localized reaction products, although the staining was decreased. In the higher pH range the reaction products became more diffuse and factors other than enzyme activity probably influence the reaction product formation. Cristae alone did not stain at any pH value tested.