title: Mitochondrial superoxide anion production and release into intermembrane space.
abstract: The topological distribution of ubiquinone in the mitochondrial respiratory chain suggests that both ubiquinone pools may participate in O2.- production and, hence, are vectorially released into the matrix and intermembrane space. Mitoplasts, obtained by either digitonin or hypotonic KCl treatment, are a suitable experimental model for measuring O2.- in the intermembrane space. The use of membrane-impermeable spin-broadening agents strengthens the notion that part of the O2.- generated by the respiratory chain may be released into the intermembrane space. This, together with the putative occurrence of a Cu, Zn-superoxide dismutase in this compartment may account for part of H2O2 released by mitochondria and contributing to a cytosolic steady-state level of this species in cytosol.
authors.affiliation: Department of Molecular Pharmacology and Toxicology, School of Pharmacy, University of Southern California, Los Angeles, California 90033, USA.
authors.forename: Derick
authors.initials: D
authors.lastname: Han
authors.forename: Fernando
authors.initials: F
authors.lastname: Antunes
authors.forename: Francesca
authors.initials: F
authors.lastname: Daneri
authors.forename: Enrique
authors.initials: E
authors.lastname: Cadenas
mesh_terms: D000818:Animals; D002458:Cell Fractionation; D004072:Digitonin; D004578:Electron Spin Resonance Spectroscopy; D004579:Electron Transport; D006861:Hydrogen Peroxide / Q000378:metabolism; D066298:In Vitro Techniques; D007425:Intracellular Membranes / Q000378:metabolism; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D008929:Mitochondria, Heart / Q000378:metabolism; D008930:Mitochondria, Liver / Q000378:metabolism; D009997:Osmotic Pressure; D010084:Oxidation-Reduction; D010617:Phenanthridines; D051381:Rats; D017208:Rats, Wistar; D013367:Submitochondrial Particles / Q000378:metabolism; D013481:Superoxides / Q000378:metabolism*
chemical_list: D010617:Phenanthridines; D013481:Superoxides; C058428:hydroethidine; D006861:Hydrogen Peroxide; D004072:Digitonin