Extramitochondrial release of hydrogen peroxide from insect and mouse liver mitochondria using the respiratory inhibitors phosphine, myxothiazol, and antimycin and spectral analysis of inhibited cytochromes

• Published in: Archives of biochemistry and biophysics Vol. 278; no. 1; pp. 65 - 72
• Main Authors: Bolter, Caroline J., Chefurka, William
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01.04.1990; Elsevier
• Subjects: Animals; ANTIBIOTICOS; ANTIBIOTICS; ANTIBIOTIQUE; Antimycin A - pharmacology; Biological and medical sciences; Cell structures and functions; Coleoptera; Curculionidae; CYTOCHROME C OXIDASE; Cytochromes - antagonists & inhibitors; ESPECTROMETRIA; Fundamental and applied biological sciences. Psychology; HYDROGEN PEROXIDE; Hydrogen Peroxide - metabolism; INHIBITION; Insecta - metabolism; INSECTICIDAS; INSECTICIDE; INSECTICIDES; Kinetics; METALLOPROTEINE; METALLOPROTEINS; METALPROTEINAS; Methacrylates; MICE; MITOCHONDRIA; Mitochondria - drug effects; Mitochondria - metabolism; Mitochondria and cell respiration; Mitochondria, Liver - drug effects; Mitochondria, Liver - metabolism; MITOCHONDRIE; MITOCONDRIA; Molecular and cellular biology; OXIDOREDUCTASES; OXIDORREDUCTASAS; OXYDOREDUCTASE; Oxygen Consumption - drug effects; PEROXIDO DE HIDROGENO; PEROXYDE D'HYDROGENE; Phosphines - pharmacology; RATON; RESPIRACION; RESPIRATION; Rotenone - pharmacology; SITOPHILUS; SITOPHILUS GRANARIUS; SOURIS; Species Specificity; SPECTROMETRIE; SPECTROMETRY; THIAZOLE; THIAZOLES; Thiazoles - pharmacology; TIAZOLES; Insecticide; Coleoptera; Insecta; Rodentia; Hydroperoxide; Vertebrata; Mitochondria; Mammalia; Mouse; Arthropoda; Curculionidae; Inhibition; Invertebrata; Sitophilus granarius; Ultraviolet visible spectrometry
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1016/0003-9861(90)90232-N

The fumigant insecticide phosphine (PH 3) is known to inhibit cytochrome c oxidase in vitro. Inhibition of the respiratory chain at this site has been shown to stimulate the generation of superoxide radicals (O 2 −), which dismutate to form hydrogen peroxide (H 2O 2). This study was performed in order to investigate the production of H 2O 2 by mitochondria isolated from granary weevil ( Sitophilus granarius) and mouse liver on exposure to PH 3. Other respiratory inhibitors, antimycin, myxothiazol, and rotenone were used with insect mitochondria. Hydrogen peroxide was measured spectrophotometrically using yeast cytochrome c peroxidase as an indicator. Insect and mouse liver mitochondria, utilizing endogenous substrate, both produced H 2O 2 after inhibition by PH 3. Insect organelles released threefold more H 2O 2 than did mouse organelles, when exposed to PH 3. Production of H 2O 2 by PH 3-treated insect mitochondria was increased significantly on addition of the substrate α-glycerophosphate. Succinate did not enhance H 2O 2 production, however, indicating that the H 2O 2 did not result from the autoxidation of ubiquinone. NAD+-linked substrates, malate and pyruvate also had no effect on H 2O 2 production, suggesting that NADH-dehydrogenase was not the source of H 2O 2. Data obtained using antimycin and myxothiazol, both of which stimulated the release of H 2O 2 from insect mitochondria, lead to the conclusion that glycerophosphate dehydrogenase is a source of H 2O 2. The effect of combining PH 3, antimycin, and myxothiazol on cytochrome spectra in insect mitochondria was also recorded. It was observed that PH 3 reduces cytochrome c oxidase but none of the other cytochromes in the electron transport chain. There was no movement of electrons to cytochrome b when insect mitochondria are inhibited with PH 3. The spectral data show that the inhibitors interact with the respiratory chain in a way that would allow the production of H 2O 2 from the sites proposed previously.