Regulation of uncoupling protein activity in phosphorylating potato tuber mitochondria.
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.
Navet
Rachel
R
Laboratory of Bioenergetics, Department of Life Sciences, Institute of Chemistry B6c, University of Liège, Sart-Tilman, B-4000 Liège, Belgium.
Douette
Pierre
P
Puttine-Marique
Florence
F
Sluse-Goffart
Claudine M
CM
Jarmuszkiewicz
Wieslawa
W
Sluse
Francis E
FE
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
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