MEDIATION OF p-AMINODIPHENYLAMINE OXIDATION VIA CYTOCHROME OXIDASE

Abstract
Manometric studies have revealed that the oxidation of p-aminodiphenylamine by Keilin and Hartree beef heart muscle particles was several-fold higher in the presence of added cytochrome c than in the absence of the pigment. The oxidation of p-aminodiphenylamine was inhibited 90% by 10–4 M cyanide. Correlated spectrophotometric studies demonstrated that the oxidation of p-aminodiphenylamine by Keilin and Hartree particles and fresh-frozen dehydrated tissue sections produced substances with identical visible and ultraviolet absorption spectra. The above experiments further indicate that the oxidation of p-aminodiphenylamine is mediated via cytochrome oxidase, and that this reagent provides valid histochemical localizations of the respiratory enzyme.