Effect of Aromatic Amines on Isolated Rat-Liver Mitochondria
Abstract
The effect of some unsubstituted aromatic amines and their o - and p -hydroxylated derivatives on isolated rat-liver mitochondria has been studied. The o -hydroxylated amines inhibited oxygen uptake in the presence of nicotinamide adenine dinucleotide-dependent respiratory substrates. Of the other compounds only 1-amino-4-naphthol inhibited oxygen uptake. The succinate oxidase system was inhibited only by 1-amino-2-naphthol and 1-amino-4-naphthol. The o -hydroxylated compounds impaired the efficiency of oxidative phosphorylation; the effect of 4-amino-3-hydroxybiphenyl was much more evident when -oxoglutarate was used as respiratory substrate. 1-Amino-2-naphthol and 1-amino-4-naphthol completely suppressed phosphate esterification. 1,2-Naphthoquinone and 1,4-naphthoquinone impaired the efficiency of oxidative phosphorylation when supported either by ß-hydroxybutyrate or by succinate. o -Aminophenol, 4-amino-3-hydroxybiphenyl, and 2-amino-1-naphthol stimulated mitochondrial adenosine triphosphatase in the presence of Mg ++ ; the last two compounds inhibited the dinitrophenol-induced adenosine triphosphatase activity. 1-Amino-2-naphthol and 1-amino-4-naphthol inhibited adenosine triphosphatase in the presence of Mg ++ and Mg ++ plus 2,4-dinitrophenol. 1 This work was partially supported by a grant from Consiglio Nazionale Delle Ricerche, Impresa di Enzimologia, Italy. 2 Present address: Chelsea College of Science and Technology, School of Pharmacy, 271/3 King St. Hammersmith, London W.6, England.