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Type: Artigo de periódico
Title: Proton Re-uptake Partitioning Between Uncoupling Protein And Atp Synthase During Benzohydroxamic Acid-resistant State 3 Respiration In Tomato Fruit Mitochondria.
Author: Jarmuszkiewicz, W
Almeida, A M
Vercesi, A E
Sluse, F E
Sluse-Goffart, C M
Abstract: The yield of oxidative phosphorylation in isolated tomato fruit mitochondria depleted of free fatty acids remains constant when respiratory rates are decreased by a factor of 3 by the addition of n-butyl malonate. This constancy makes the determination of the contribution of the linoleic acid-induced energy-dissipating pathway by the ADP/O method possible. No decrease in membrane potential is observed in state 3 respiration with increasing concentration of n-butyl malonate, indicating that the rate of ATP synthesis is steeply dependent on membrane potential. Linoleic acid decreases the yield of oxidative phosphorylation in a concentration-dependent manner by a pure protonophoric process like that in the presence of FCCP. ADP/O measurements allow calculation of the part of respiration leading to ATP synthesis and the part of respiration sustained by the dissipative H(+) re-uptake induced by linoleic acid. Respiration sustained by this energy-dissipating process remains constant at a given LA concentration until more than 50% inhibition of state 3 respiration by n-butyl malonate is achieved. The energy dissipative contribution to oxygen consumption is proposed to be equal to the protonophoric activity of plant uncoupling protein divided by the intrinsic H(+)/O of the cytochrome pathway. It increases with linoleic acid concentration, taking place at the expense of ADP phosphorylation without an increase in the respiration.
Subject: Hydroxamic Acids
Lycopersicon Esculentum
Oxidative Phosphorylation
Proton Pumps
Proton-translocating Atpases
Rights: fechado
Identifier DOI: 
Date Issue: 2000
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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