Hydrogen peroxide efflux from muscle mitochondria underestimates matrix superoxide production--a correction using glutathione depletion.

ABSTRACT: The production of H(2)O(2) by isolated mitochondria is frequently used as a measure of mitochondrial superoxide formation. Matrix superoxide dismutase quantitatively converts matrix superoxide to H(2)O(2). However, matrix enzymes such as the glutathione peroxidases can consume H(2)O(2) and compete with efflux of H(2)O(2), causing an underestimation of superoxide production. To assess this underestimate, we depleted matrix glutathione in rat skeletal muscle mitochondria by more than 90% as a consequence of pretreatment with 1-chloro-2,4-dintrobenzene (CDNB). The pretreatment protocol strongly diminished the mitochondrial capacity to consume exogenous H(2)O(2), consistent with decreased peroxidase capacity, but avoided direct stimulation of superoxide production from complex I. It elevated t

SUBMITTER: Treberg JR 

PROVIDER: S-EPMC2891561 | biostudies-literature | 2010 Jul

REPOSITORIES: biostudies-literature