title: Regulation of uncoupling protein activity in phosphorylating potato tuber mitochondria.
abstract: In isolated potato tuber mitochondria, palmitic acid (PA) can induce a H+ leak inhibited by GTP in the phosphorylating (state 3) respiration but not in the resting (state 4) respiration. The PA-induced H+ leak is constant when state 3 respiration is decreased by an inhibition of the succinate uptake with n-butyl malonate (nBM). We show that the efficiency of inhibition by GTP is decreased when state 3 respiration is progressively inhibited by antimycin A (AA) and is restored following subsequent addition of nBM. We propose that in phosphorylating potato tuber mitochondria, the redox state of ubiquinone, which can antagonistically be varied with AA and nBM, modulates inhibition of the PA-activated UCP-sustained H+ leak by GTP.
authors.affiliation: Laboratory of Bioenergetics, Department of Life Sciences, Institute of Chemistry B6c, University of Liège, Sart-Tilman, B-4000 Liège, Belgium.
authors.forename: Rachel
authors.initials: R
authors.lastname: Navet
authors.forename: Pierre
authors.initials: P
authors.lastname: Douette
authors.forename: Florence
authors.initials: F
authors.lastname: Puttine-Marique
authors.forename: Claudine M
authors.initials: CM
authors.lastname: Sluse-Goffart
authors.forename: Wieslawa
authors.initials: W
authors.lastname: Jarmuszkiewicz
authors.forename: Francis E
authors.initials: FE
authors.lastname: Sluse
mesh_terms: D019069:Cell Respiration / Q000187:drug effects; D003609:Dactinomycin / Q000494:pharmacology; D004583:Electrons; D005230:Fatty Acids, Nonesterified / Q000378:metabolism / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000494:pharmacology; D007425:Intracellular Membranes / Q000378:metabolism; D008314:Malonates / Q000494:pharmacology; D008565:Membrane Proteins / Q000378:metabolism*; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010085:Oxidative Phosphorylation; D019308:Palmitic Acid / Q000378:metabolism / Q000494:pharmacology*; D010940:Plant Proteins / Q000378:metabolism*; D035281:Plant Tubers / Q000187:drug effects / Q000378:metabolism; D011522:Protons; D011198:Solanum tuberosum / Q000187:drug effects / Q000378:metabolism*; D014451:Ubiquinone / Q000378:metabolism
chemical_list: D005230:Fatty Acids, Nonesterified; D008314:Malonates; D008565:Membrane Proteins; D024101:Mitochondrial Proteins; D010940:Plant Proteins; D011522:Protons; D014451:Ubiquinone; D003609:Dactinomycin; D019308:Palmitic Acid; C006860:2-n-butylmalonate; D006160:Guanosine Triphosphate