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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, AM
Vercesi, AE
Sluse, FE
Sluse-Goffart, CM
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.
Country: EUA
Editor: Amer Soc Biochemistry Molecular Biology Inc
Citation: Journal Of Biological Chemistry. Amer Soc Biochemistry Molecular Biology Inc, v. 275, n. 18, n. 13315, n. 13320, 2000.
Rights: fechado
Identifier DOI: 10.1074/jbc.275.18.13315
Date Issue: 2000
Appears in Collections:Unicamp - Artigos e Outros Documentos

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