Mitochondrial matrix reactive oxygen species production is very sensitive to mild uncoupling.
Mitochondria produce ROS (reactive oxygen species) as a by-product of aerobic respiration. Several studies in mammals and birds suggest that the most physiologically relevant ROS production is from complex I following reverse electron flow, and is highly sensitive to membrane potential. A study of Drosophila mitochondria respiring glycerol 3-phosphate revealed that membrane potential-sensitive ROS production from complex I following reverse electron flow was on the matrix side of the inner membrane. A 10 mV decrease in membrane potential was enough to abolish around 70% of the ROS produced by complex I under these conditions. Another important ROS generator in this model, glycerol-3-phosphate dehydrogenase, produced ROS mostly to the cytosolic side; this ROS production was totally insensitive to a small decrease in membrane potential (10 mV). Thus mild uncoupling may be particularly significant for ROS production from complex I on the matrix side of the mitochondrial inner membrane.
Miwa
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MRC Dunn Human Nutrition Unit, Hills Road, Cambridge CB2 2XY, U.K. sm@mrc-dunn.cam.ac.uk
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D000818:Animals; D004330:Drosophila; D008564:Membrane Potentials; D008928:Mitochondria / Q000378:metabolism*; D017382:Reactive Oxygen Species
D017382:Reactive Oxygen Species