scholarly journals Interaction of Benzylaminopurine with Electron Transport in Plant Mitochondria during Malate Oxidation

1983 ◽  
Vol 73 (4) ◽  
pp. 945-948 ◽  
Author(s):  
Michèle Chauveau ◽  
Pierre Dizengremel ◽  
Jean Roussaux
Keyword(s):  
Electron Transport ◽  
Plant Mitochondria ◽  
Malate Oxidation

Effect of NAD and Rotenone on the Partitioning of Malate Oxidation Between Malate Dehydrogenase and Malic Enzyme in Isolated Plant Mitochondria

1985 ◽  
Vol 12 (3) ◽  
pp. 229 ◽  
Author(s):  
JH Bryce ◽  
JT Wiskich
Keyword(s):  
Energy Metabolism ◽  
Electron Transport ◽  
Oxygen Uptake ◽  
Malate Dehydrogenase ◽  
Malic Enzyme ◽  
Plant Mitochondria ◽  
Metabolizing Enzyme ◽  
Stimulation Of ◽  
Malate Metabolism ◽  
Malate Oxidation

Our aim was to determine whether there is a specific link between NAD-malic enzyme and the rotenone- insensitive bypass of electron transport. Mitochondria were isolated from fresh beetroot tissue, aged beetroot slices, and turnips. Oxygen uptake and pyruvate production were measured in reactions where these mitochondria were metabolizing malate at pH 6.8 in the presence of glutamate, to facilitate the removal of oxaloacetate, and in its absence. In the absence of glutamate there was substantial activity of malic enzyme. NAD+ (577 �M) prevented a fall in oxygen uptake by stimulating malic enzyme. Rotenone (19 �M) reduced oxygen uptake. This inhibited rate was stimulated by NAD+ due, in particular, to a stimulation of malic enzyme. We conclude that the stimulation of malate metabolism by NAD+ is accounted for by malic enzyme due to the unfavourable equilibrium of malate dehydrogenase for malate oxidation and the resultant accumulation of oxaloacetate, and not to any specific link between malic enzyme and the rotenone-insensitive bypass. In the presence of glutamate, malate dehydrogenase was the predominant malate metabolizing enzyme. Oxygen uptake and malic enzyme were stimulated and inhibited by NAD+ and rotenone, respectively. In the presence of rotenone, NAD+ stimulated oxygen uptake and increased the percentage due to malic enzyme. This stimulation is accounted for by the higher Kin of the rotenone-insensitive dehydrogenase for NADH and the unfavourable equilibrium position of malate dehydrogenase resulting in activation of malic enzyme only. We conclude that malic enzyme is not specifically linked to the rotenone-insensitive pathway of electron transport. This has important implications for the regulation of energy metabolism in plants.

Site of action of nonheme iron in the malate (flavine adenine dinucleotide) pathway of Mycobacterium phlei

1976 ◽  
Vol 22 (7) ◽  
pp. 1054-1057 ◽  
Author(s):  
A. K. Tyagi ◽  
T. L. Prasada Reddy ◽  
T. A. Venkitasubramanian
Keyword(s):  
Electron Transport ◽  
Ultraviolet Light ◽  
Nonheme Iron ◽  
Paramagnetic Resonance ◽  
Iron Protein ◽  
Mycobacterium Phlei ◽  
Diphenyl Tetrazolium Bromide ◽  
Electron Paramagnetic ◽  
Soluble Components ◽  
Malate Oxidation

Irradiation with ultraviolet light (360 nm) of cell-free extracts, electron-transport particles, and soluble components from Mycobacterium phlei resulted in the loss of malate oxidation by the flavine adenine dinucleotide pathway both in cell-free extracts and reconstituted systems. Addition of vitamin K1 restored the loss to the extent of 14% and 11% in cell-free extracts and reconstituted systems respectively. Electron-transport particles from M. phlei upon reduction with malate exhibited electron-paramagnetic resonance signals at g = 2.002 and 1.94, characteristic of napthosemiquinone and nonheme iron protein, respectively. Upon irradiating the particles with ultraviolet light (360 nm) these signals were not observed. Particulate flavine-adenine-dinucleotide-dependent malate dehydrogenase (EC 1.1.1.37) of M. phlei assayed by the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyl tetrazolium bromide and phenazine methosulfate–2,6-dichlorophenolindophenol systems, which trap electrons at cytochrome c and at the flavine level respectively, was inhibited by o-phenanthroline. These observations suggest that nonheme iron protein is sensitive to ultraviolet light (360 nm) and participates before or in combination with flavine in the malate (flavine adenine dinucleotide) pathway of M. phlei.

scholarly journals Regulation of Electron Transport in Plant Mitochondria under State 4 Conditions

1991 ◽  
Vol 95 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Anthony L. Moore ◽  
Ian B. Dry ◽  
Joseph T. Wiskich
Keyword(s):  
Electron Transport ◽  
Plant Mitochondria

Ubiquinone Redox Behavior in Plant Mitochondria during Electron Transport

1995 ◽  
Vol 317 (1) ◽  
pp. 156-160 ◽  
Author(s):  
M. Ribascarbo ◽  
J.T. Wiskich ◽  
J.A. Berry ◽  
J.N. Siedow
Keyword(s):  
Electron Transport ◽  
Plant Mitochondria ◽  
Redox Behavior

scholarly journals Stress signalling dynamics of the mitochondrial electron transport chain and oxidative phosphorylation system in higher plants

2019 ◽  
Vol 125 (5) ◽  
pp. 721-736 ◽  
Author(s):  
Corentin Dourmap ◽  
Solène Roque ◽  
Amélie Morin ◽  
Damien Caubrière ◽  
Margaux Kerdiles ◽  
...  
Keyword(s):  
Climate Change ◽  
Electron Transport ◽  
Oxidative Phosphorylation ◽  
Electron Transport Chain ◽  
Plant Mitochondria ◽  
Mitochondrial Electron Transport Chain ◽  
Oxidative Phosphorylation System ◽  
Transport Chain ◽  
Wide Range ◽  
Stress Signalling

Abstract Background Mitochondria play a diversity of physiological and metabolic roles under conditions of abiotic or biotic stress. They may be directly subjected to physico-chemical constraints, and they are also involved in integrative responses to environmental stresses through their central position in cell nutrition, respiration, energy balance and biosyntheses. In plant cells, mitochondria present various biochemical peculiarities, such as cyanide-insensitive alternative respiration, and, besides integration with ubiquitous eukaryotic compartments, their functioning must be coupled with plastid functioning. Moreover, given the sessile lifestyle of plants, their relative lack of protective barriers and present threats of climate change, the plant cell is an attractive model to understand the mechanisms of stress/organelle/cell integration in the context of environmental stress responses. Scope The involvement of mitochondria in this integration entails a complex network of signalling, which has not been fully elucidated, because of the great diversity of mitochondrial constituents (metabolites, reactive molecular species and structural and regulatory biomolecules) that are linked to stress signalling pathways. The present review analyses the complexity of stress signalling connexions that are related to the mitochondrial electron transport chain and oxidative phosphorylation system, and how they can be involved in stress perception and transduction, signal amplification or cell stress response modulation. Conclusions Plant mitochondria are endowed with a diversity of multi-directional hubs of stress signalling that lead to regulatory loops and regulatory rheostats, whose functioning can amplify and diversify some signals or, conversely, dampen and reduce other signals. Involvement in a wide range of abiotic and biotic responses also implies that mitochondrial stress signalling could result in synergistic or conflicting outcomes during acclimation to multiple and complex stresses, such as those arising from climate change.

The multiplicity of dehydrogenases in the electron transport chain of plant mitochondria

Mitochondrion ◽  
2008 ◽  
Vol 8 (1) ◽  
pp. 47-60 ◽  
Author(s):  
Allan G. Rasmusson ◽  
Daniela A. Geisler ◽  
Ian M. Møller
Keyword(s):  
Electron Transport ◽  
Electron Transport Chain ◽  
Plant Mitochondria ◽  
Transport Chain

scholarly journals Role of Nonohmicity in the Regulation of Electron Transport in Plant Mitochondria

1989 ◽  
Vol 91 (2) ◽  
pp. 487-492 ◽  
Author(s):  
David G. Whitehouse ◽  
Anne-Catherine Fricaud ◽  
Anthony L. Moore
Keyword(s):  
Electron Transport ◽  
Plant Mitochondria
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