Superoxide and hydrogen peroxide production by Drosophila mitochondria.

TitleSuperoxide and hydrogen peroxide production by Drosophila mitochondria.
Publication TypeJournal Article
Year of Publication2003
AuthorsMiwa, S, St-Pierre, J, Partridge, L, Brand, MD
JournalFree Radic Biol Med
Date Published2003 Oct 15
KeywordsAnimals, Antimycin A, Cytochromes c, Cytosol, Drosophila melanogaster, Electron Transport, Electron Transport Complex III, Fluorometry, Glycerolphosphate Dehydrogenase, Hydrogen Peroxide, Mitochondria, NAD, Superoxide Dismutase, Superoxides

Drosophila melanogaster is a key model organism for genetic investigation of the role of free radicals in aging, but biochemical understanding is lacking. Superoxide production by Drosophila mitochondria was measured fluorometrically as hydrogen peroxide, using its dependence on substrates, inhibitors, and added superoxide dismutase to determine sites of production and their topology. Glycerol 3-phosphate dehydrogenase and center o of complex III in the presence of antimycin had the greatest maximum capacities to generate superoxide on the cytosolic side of the inner membrane. Complex I had significant capacity on the matrix side. Center i of complex III, cytochrome c, and complex IV produced no superoxide. Native superoxide generation by isolated mitochondria was also measured without added inhibitors. There was a high rate of superoxide production with sn-glycerol 3-phosphate as substrate; two-thirds mostly from glycerol 3-phosphate dehydrogenase on the cytosolic side and one-third on the matrix side from complex I following reverse electron transport. There was little superoxide production from any site with NADH-linked substrate. Superoxide production by complex I following reverse electron flow from glycerol 3-phosphate was particularly sensitive to membrane potential, decreasing 70% when potential decreased 10 mV, showing that mild uncoupling lowers superoxide production in the matrix very effectively.

Alternate JournalFree Radic. Biol. Med.
Citation Key10.1016/s0891-5849(03)00464-7
PubMed ID14556858
Grant ListSF19106 / / Biotechnology and Biological Sciences Research Council / United Kingdom