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Succinate-dependent metabolism in Trypanosoma cruzi epimastigotes

Denicola-Seoane, Ana ; Rubbo, Homero ; Prodanov, Eugenio ; Turrens, Julio F.

Molecular and biochemical parasitology, 1992-08, Vol.54 (1), p.43-50 [Periódico revisado por pares]

AMSTERDAM: Elsevier B.V

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Título:
Succinate-dependent metabolism in Trypanosoma cruzi epimastigotes
Autor: Denicola-Seoane, Ana ; Rubbo, Homero ; Prodanov, Eugenio ; Turrens, Julio F.
Assuntos: Animals ; Biochemistry & Molecular Biology ; Biological and medical sciences ; Carbohydrate metabolism ; Chagas' disease ; Fumarate reductase ; Fumarates - metabolism ; Fundamental and applied biological sciences. Psychology ; Glucose - metabolism ; Hydrogen peroxide ; Hydrogen Peroxide - metabolism ; Life Sciences & Biomedicine ; NAD - metabolism ; Oxygen Consumption - physiology ; Parasitology ; Proline - metabolism ; Protozoa ; Respiratory chain ; Science & Technology ; Succinate ; Succinates - metabolism ; Succinic Acid ; Trypanosoma cruzi ; Trypanosoma cruzi - metabolism
É parte de: Molecular and biochemical parasitology, 1992-08, Vol.54 (1), p.43-50
Notas: ObjectType-Article-2
SourceType-Scholarly Journals-1
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Descrição: Trypanosoma cruzi epimastigotes permeabilized with digitonin (65 μg (mg protein) −1) to measure mitochondrial respiration were exposed to different substrates. Although none of the NADH-dependent substrates stimulated respiration, succinate supported not only oxygen consumption but also oxidative phosphorylation (respiratory control ratio of (1.9 ± 0.3) indicating that the mitochondria were coupled. The rate of NADH-dependent oxygen consumption by membrane fractions (9.4 ± 0.7 nmol min −1 (mg protein) −1) was reduced by 50% upon addition of catalase indicating that the electrons from NADH oxidation reduced oxygen to H 2O 2. NADH-dependent H 2O 2 production (16 ± 1 nmol min −1 (mg protein) −1) was confirmed using cytochrome c peroxidase. This activity was inhibited by fumarate by 70%, suggesting a competition between fumarate and oxygen for the electrons from NADH, probably at the fumarate reductase level. The respiratory chain inhibitor antimycin blocked both respiration by intact cells and succinate-dependent cytochrome c by isolated membranes. No inhibition by antimycin was observed when NADH replaced succinate as an electron donor, indicating that the electrons from NADH oxidation reduced cytochrome c through a different route. Malonate blocked not only succinate-cytochrome c reductase and fumarate reductase, but also intact cell motility. These results suggest that succinate has a central role in the intermediate metabolism of T. cruzi, as it may be used for respiration or excreted to the extracellular space under anaerobic conditions. In addition, 2 potential sources of H 2O 2 were tentatively identified as: (a) the enzyme fumarate reductase; and (b) a succinate-dependent site, which may be the semiquinone form of Coenzyme Q 9, as in mammalian mitochondria.
Editor: AMSTERDAM: Elsevier B.V
Idioma: Inglês

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Succinate-dependent metabolism in Trypanosoma cruzi epimastigotes

Denicola-Seoane, Ana ; Rubbo, Homero ; Prodanov, Eugenio ; Turrens, Julio F.

AMSTERDAM: Elsevier B.V

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