What are the sources of hydrogen peroxide production by heart mitochondria?

• Published in: Biochimica et biophysica acta 2010-06, Vol.1797 (6-7), p.939-944
• Main Authors: Grivennikova, Vera G., Kareyeva, Alexandra V., Vinogradov, Andrei D.
• Format: Article
• Language: English
• Subjects: Adenosine Diphosphate - pharmacology; Ammonium; Animals; Complex I; Electron Transport Complex I - metabolism; Glutamic Acid - metabolism; Hydrogen Peroxide - metabolism; Hydrogen peroxide production; In Vitro Techniques; Malates - metabolism; Matrix proteins; Mitochondria; Mitochondria, Heart - drug effects; Mitochondria, Heart - metabolism; Mitochondrial Proteins - metabolism; NAD - metabolism; Oxidation-Reduction; Oxygen Consumption; Quaternary Ammonium Compounds - pharmacology; Rats; Respiratory activity; Succinic Acid - metabolism
• ISSN: 0005-2728; 0006-3002; 1879-2650
• DOI: 10.1016/j.bbabio.2010.02.013

Coupled rat heart mitochondria produce externally hydrogen peroxide at the rates which correspond to about 0.8 and 0.3% of the total oxygen consumption at State 4 with succinate and glutamate plus malate as the respiratory substrates, respectively. Stimulation of the respiratory activities by ADP (State 4–State 3 transition) decreases the succinate- and glutamate plus malate-supported H2O2 production 8- and 1.3-times, respectively. NH4+ strongly stimulates hydrogen peroxide formation with either substrate without any effect on State 4 and/or State 3 respiration. Rotenone-treated, alamethicin-permeabilized mitochondria catalyze NADH-supported H2O2 production at a rate about 10-fold higher than that seen in intact mitochondria under optimal (State 4 succinate-supported respiration in the presence of ammonium chloride) conditions. NADH-supported hydrogen peroxide production by the rotenone-treated mitochondria devoid of a permeability barrier for H2O2 diffusion by alamethicin treatment are only partially (∼50%) sensitive to the Complex I NADH binding site-specific inhibitor, NADH-OH. The residual activity is strongly (∼6-fold) stimulated by ammonium chloride. NAD+ inhibits both Complex I-mediated and ammonium-stimulated H2O2 production. In the absence of stimulatory ammonium about half of the total NADH-supported hydrogen peroxide production is catalyzed by Complex I. In the presence of ammonium about 90% of the total hydrogen peroxide production is catalyzed by matrix located, ammonium-dependent enzyme(s).