Production of Superoxide Radicals during Bacterial Respiration

Summary: When sucrose or acetate was added to washed suspensions of a number of aerobic bacteria, exogenous ferricytochrome c 3+ was reduced, luminol chemiluminescence was enhanced and the rate of adrenaline auto-oxidation was increased. Superoxide dismutase from bovine erythrocytes inhibited all of there reactions, suggesting that superoxide radicals (O- 2) are formed during aerobic bacterial metabolism. Superoxide radicals were probably generated during respiratory chain activity because O- 2 production by intact bacteria was stimulated by antimycin A and the highest O- 2-producing activity was observed with membrane fractions with a high concentration of cytochromes. Exogenous superoxide dismutase partially inhibited NADH-dependent oxgyen consumption by membrane particles of Brevibacterium flavum 22LD.