1,720,977 research outputs found
Manipulation of iron and energy status of cells as a tool fot triggering apoptosis. Key role for inactivation of mitochondrial ATP synthase
No full textH2O2 induces apoptosis in heme-synthesizig erytrholeukemia cells with a mechanism indeoendent from nF-kB activation and mediated by decline in mitochondrial bioenergy
No full textInactivation of mitochondrial ATPsynthase through manipulation of iron status as a tool for triggering apoptosis
No full textEndogenous pro-oxidant status and H2O2-mediated impairment of cell mitochondrial functions, ATP content and proliferative capacity
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Down-regulation of the mitochondrial ATP synthase in Friend's erythroleukemia cells induced to differentiation
No full textDifferent mechanisms of H2O2-dependent damage to mitochondrial F0F1ATPsynthase mediated by different intracellular iron chelates
No full textDifferent Fe molecular species mediate selective H2O2- damage to different moieties ofl F0F1ATPsynthase in intact cells, isolated mitochonria and proteoliposomes
No full textRedox properties of iron in the binding site(s) of F1ATPase from mammalian mitochondria and Thermophilic bacterium PS3: a comparative study
No full textIron ions in the two iron centers of beef heart mitochondrial F1ATPase, which we have been recently characterized (FEBS Letters 1996, 379, 231-235), exhibit different redox properties. In fact, the ATP-dependent site is able to maintain iron in the redox state of Fe(II) even in the absence of reducing agents, whereas in the nucleotide-independent site iron is oxidized to Fe(III) upon removal of the reductant. Fe(III) ions in the two sites display different reactivity towards H2O2, because only Fe(III) bound in the nucleotide-independent site rapidly reacts with H2O2 thus mediating a 30% enzyme inactivation. Thermophilic bacterium PS3 bears one Fe(III) binding site, which takes up Fe(III) either in the absence or presence of nucleotides and is unable to maintain iron in the redox state of Fe(II) in the absence of ascorbate. Fe(III) bound in thermophilic F1ATPase in a molar ratio 1:1 rapidly reacts with H2O2 mediating a 30% enzyme inactivation. These results support the presence in mitochondrial and thermophilic F1ATPase of a conserved site involved in iron binding and in oxidative inactivation, in which iron exhibits similar redox properties. On the other hand, at variance with thermophilic F1ATPase, the mitochondrial enzyme has the possibility of maintaining one equivalent of Fe(II) in its peculiar ATP-dependent site, besides one equivalent of Fe(III) in the conserved nucleotide-independent site. In this case mitochondrial F1ATPase undergoes a higher inactivation (75%) upon exposure to H2O2. Under all conditions the inactivation is significantly prevented by PBN and DMSO but not by Cu, Zn superoxide dismutase, thus suggesting the formation of OH radicals as mediators of the oxidative damage. No dityrosines, carbonyls or oxidized thiols are formed. In addition, in any cases no protein fragmentation or aggregation is observed upon the treatment with H2O2
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