title: Glycerophosphate-dependent hydrogen peroxide production by brown adipose tissue mitochondria and its activation by ferricyanide.
abstract: Oxidation of glycerophosphate (GP) by brown adipose tissue mitochondria in the presence of antimycin A was found to be accompanied by significant production of hydrogen peroxide. GP-dependent hydrogen peroxide production could be detected by p-hydroxyphenylacetate fluorescence changes or as an antimycin A-insensitive oxygen consumption. One-electron acceptor, potassium ferricyanide, highly stimulated the rate of GP-dependent antimycin A-insensitive oxygen uptake, which was prevented by inhibitors of mitochondrial GP dehydrogenase (mGPDH) or by coenzyme Q (CoQ). GP-dependent ferricyanide-induced peroxide production was also determined luminometrically, using mitochondria or partially purified mGPDH. Ferricyanide-induced peroxide production was negligible, when succinate or NADH was used as a substrate. These results indicate that hydrogen peroxide is produced directly by mGPDH and reflect the differences in the transport of reducing equivalents from mGPDH and succinate dehydrogenase to the CoQ pool. The data suggest that more intensive production of reactive oxygen species may be present in mammalian cells with active mGPDH.
authors.affiliation: Institute of Physiology and Center for Integrated Genomics, Academy of Sciences of the Czech Republic, Prague. drahota@biomed.cas.cz
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Drahota
authors.forename: Subir K R
authors.initials: SK
authors.lastname: Chowdhury
authors.forename: Daniel
authors.initials: D
authors.lastname: Floryk
authors.forename: Tomás
authors.initials: T
authors.lastname: Mrácek
authors.forename: Jirí
authors.initials: J
authors.lastname: Wilhelm
authors.forename: Hana
authors.initials: H
authors.lastname: Rauchová
authors.forename: Giorgio
authors.initials: G
authors.lastname: Lenaz
authors.forename: Josef
authors.initials: J
authors.lastname: Houstek
mesh_terms: D002001:Adipose Tissue, Brown / Q000187:drug effects* / Q000378:metabolism*; D000818:Animals; D002374:Catalase / Q000378:metabolism / Q000494:pharmacology; D006224:Cricetinae; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005292:Ferricyanides / Q000494:pharmacology*; D005993:Glycerolphosphate Dehydrogenase / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism; D005994:Glycerophosphates / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D066298:In Vitro Techniques; D008163:Luminescent Measurements; D008297:Male; D008647:Mesocricetus; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D008954:Models, Biological; D017382:Reactive Oxygen Species / Q000378:metabolism; D014451:Ubiquinone / Q000378:metabolism / Q000494:pharmacology
chemical_list: D004791:Enzyme Inhibitors; D005292:Ferricyanides; D005994:Glycerophosphates; D017382:Reactive Oxygen Species; D014451:Ubiquinone; D006861:Hydrogen Peroxide; D005993:Glycerolphosphate Dehydrogenase; D002374:Catalase; C028033:potassium ferricyanide