Enzymic reduction of 2:4-dinitrophenol by rat-tissue homogenates

During an investigation into the toxic properties of 3:5-dinitro-o-cresol (DNOC) and 2:4-dinitrophenol (DNP) the breakdown ofthese substances by animal tissues in vitro was studied. Dinitrophenol and di- nitro-o-cresol have been studied as inhibitors of phosphorylation in various enzyme systems and have been shown to affect the metabolism of tissues in vitro, but little has been reported of the effect of such systems on the dinitrophenol molecule. There is some information on the metabolic products of dinitrophenol by Magne, Mayer & Plantefol (1932) who state that the excretion products in the urine after administration of dinitrophenol to man and dogs were unchanged dinitrophenol and 2-amino- 4-nitrophenol. Later, Greville & Stern (1935) demon- strated that 2-amino-4-nitrophenol was the main product after dinitrophenol had been in contact with a bacterial succinic dehydrogenase system.