The role of mild uncoupling and non‐coupled respiration in the regulation of hydrogen peroxide generation by plant mitochondria
Open Access
- 23 May 2000
- journal article
- Published by Wiley in FEBS Letters
- Vol. 474 (1) , 53-57
- https://doi.org/10.1016/s0014-5793(00)01576-3
Abstract
The roles of mild uncoupling caused by free fatty acids (mediated by plant uncoupling mitochondrial protein (PUMP) and ATP/ADP carrier (AAC)) and non‐coupled respiration (alternative oxidase (AO)) on H2O2 formation by plant mitochondria were examined. Both laurate and oleate prevent H2O2 formation dependent on the oxidation of succinate. Conversely, these free fatty acids (FFA) only slightly affect that dependent on malate plus glutamate oxidation. Carboxyatractylate (CAtr), an inhibitor of AAC, completely inhibits oleate‐ or laurate‐stimulated oxygen consumption linked to succinate oxidation, while GDP, an inhibitor of PUMP, caused only a 30% inhibition. In agreement, CAtr completely restores the oleate‐inhibited H2O2 formation, while GDP induces only a 30% restoration. Both oleate and laurate cause a mild uncoupling of the electrical potential (generated by succinate), which is then followed by a complete collapse with a sigmoidal kinetic. FFA also inhibit the succinate‐dependent reverse electron transfer. Diamide, an inhibitor of AO, favors the malate plus glutamate‐dependent H2O2 formation, while pyruvate (a stimulator of AO) inhibits it. These results show that the succinate‐dependent H2O2 formation occurs at the level of Complex I by a reverse electron transport. This generation appears to be prevented by mild uncoupling mediated by FFA. The anionic form of FFA appears to be shuttled by AAC rather than PUMP. The malate plus glutamate‐dependent H2O2 formation is, conversely, mainly prevented by non‐coupled respiration (AO).Keywords
This publication has 39 references indexed in Scilit:
- Hydrogen peroxide generation by higher plant mitochondria oxidizing complex I or complex II substratesFEBS Letters, 1999
- Fatty acids as natural uncouplers preventing generation of O⋅−2 and H2O2 by mitochondria in the resting stateFEBS Letters, 1998
- THE OXIDATIVE BURST IN PLANT DISEASE RESISTANCEAnnual Review of Plant Biology, 1997
- The oxidative burst in plant defense: Function and signal transductionPhysiologia Plantarum, 1996
- Effect of cyclosporin A on energy coupling in pea stem mitochondriaFEBS Letters, 1995
- ATP/ADP antiporter is involved in uncoupling of plant mitochondria induced by low concentrations of palmitateFEBS Letters, 1994
- Protection against oxygen radicals: an important defence mechanism studied in transgenic plantsPlant, Cell & Environment, 1994
- Does the alternative pathway ameliorate chilling injury in sensitive plant tissues?Physiologia Plantarum, 1993
- Fatty acid circuit as a physiological mechanism of uncoupling of oxidative phosphorylationFEBS Letters, 1991
- Thermogenic Respiration in AroidsAnnual Review of Plant Physiology, 1975