UNASSIGNED: The sites and rates of mitochondrial production of @entity224 and @entity274 in vivo are not yet defined. At least 10 different mitochondrial sites can generate these species. Each site has a different maximum capacity (e.g. the outer @entity9151 site in complex III (site IIIQo) has a very high capacity in @entity35 skeletal muscle mitochondria, whereas the @entity1785 site in complex I (site IF) has a very low capacity). The maximum capacities can greatly exceed the actual rates observed in the absence of electron transport chain inhibitors, so maximum capacities are a poor guide to actual rates. Here, we use new approaches to measure the rates at which different mitochondrial sites produce @entity224 / @entity274 using isolated muscle mitochondria incubated in media mimicking the cytoplasmic substrate and effector mix of skeletal muscle during rest and exercise. We find that four or five sites dominate during rest in this ex vivo system. Remarkably, the @entity9151 site in complex I (site IQ) and the @entity1785 site in complex II (site IIF) each account for about a quarter of the total measured rate of @entity274 production. Site IF, site IIIQo, and perhaps site EF in the b-oxidation pathway account for most of the remainder. Under conditions mimicking mild and intense aerobic exercise, total production is much less, and the low capacity site IF dominates. These results give novel insights into which mitochondrial sites may produce @entity224 / @entity274 in vivo.

Sites of XXXX and Hydrogen Peroxide Production by Muscle Mitochondria Assessed ex Vivo under Conditions Mimicking Rest and Exercise.

@entity274 :: ('CHEBI:16240', 'Chemical') :: ['H2O2'] @entity9151 :: ('CHEBI:17594', 'Chemical') :: ['quinol'] @entity1785 :: ('MESH:C024132', 'Chemical') :: ['flavin'] @entity35 :: ('10116', 'Species') :: ['rat'] @entity224 :: ('MESH:D013481', 'Chemical') :: ['superoxide']
@entity224 :: (MESH:D013481,Chemical) :: ['Superoxide']
