scholarly journals Closing the gap: yeast electron‐transferring flavoprotein links the oxidation of d ‐lactate and d ‐α‐hydroxyglutarate to energy production via the respiratory chain

FEBS Journal ◽  
2019 ◽  
Vol 286 (18) ◽  
pp. 3611-3628 ◽  
Author(s):  
Marina Toplak ◽  
Julia Brunner ◽  
Chaitanya R. Tabib ◽  
Peter Macheroux
Keyword(s):  
Respiratory Chain ◽  
Energy Production ◽  
Closing The Gap ◽  
Electron Transferring Flavoprotein

scholarly journals Nitric oxide and platelet energy metabolism.

2004 ◽  
Vol 51 (3) ◽  
pp. 789-803 ◽  
Author(s):  
Marian Tomasiak ◽  
Halina Stelmach ◽  
Tomasz Rusak ◽  
Jolanta Wysocka
Keyword(s):  
Nitric Oxide ◽  
Cytochrome Oxidase ◽  
Respiratory Chain ◽  
Energy Production ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Antimycin A ◽  
No Donors ◽  
Mitochondrial Energy Production ◽  
Induced Aggregation ◽  
Platelet Secretion

This study was undertaken to determine whether nitric oxide (NO) can affect platelet responses through the inhibition of energy production. It was found that NO donors: S-nitroso-N-acetylpenicyllamine, SNAP, (5-50 microM) and sodium nitroprusside, SNP, (5-100 microM) inhibited collagen- and ADP-induced aggregation of porcine platelets. The corresponding IC50 values for SNAP and SNP varied from 5 to 30 microM and from 9 to 75 microM, respectively. Collagen- and thrombin-induced platelet secretion was inhibited by SNAP (IC50 = 50 microM) and by SNP (IC50 = 100 microM). SNAP (20-100 microM), SNP (10-200 microM) and collagen (20 microg/ml) stimulated glycolysis in intact platelets. The degree of glycolysis stimulation exerted by NO donors was similar to that produced by respiratory chain inhibitors (cyanide and antimycin A) or uncouplers (2,4-dinitrophenol). Neither the NO donors nor the respiratory chain blockers affected glycolysis in platelet homogenate. SNAP (20-100 microM) and SNP (50-200 microM) inhibited oxygen consumption by platelets. The effect of SNP and SNAP on glycolysis and respiration was not reduced by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one, a selective inhibitor of NO-stimulated guanylate cyclase. SNAP (5-100 microM) and SNP (10-300 microM) inhibited the activity of platelet cytochrome oxidase and had no effect on NADH:ubiquinone oxidoreductase and succinate dehydrogenase. Blocking of the mitochondrial energy production by antimycin A slightly affected collagen-evoked aggregation and strongly inhibited platelet secretion. The results indicate that: 1) in porcine platelets NO is able to diminish mitochondrial energy production through the inhibition of cytochrome oxidase, 2) the inhibitory effect of NO on platelet secretion (but not aggregation) can be attributed to the reduction of mitochondrial energy production.

Captopril increased mitochondrial coenzyme Q10level, improved respiratory chain function and energy production in the left ventricle in rabbits with smoke mitochondrial cardiomyopathy

BioFactors ◽  
1999 ◽  
Vol 10 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Anna Gvozdjáková ◽  
Fedor Šimko ◽  
Jarmila Kucharská ◽  
Zuzana Braunová ◽  
Peter Pšenek ◽  
...  
Keyword(s):  
Left Ventricle ◽  
Respiratory Chain ◽  
Energy Production ◽  
Mitochondrial Cardiomyopathy

An improvement in the calculation of the efficiency of oxidative phosphorylation and rate of energy dissipation in mitochondria

2014 ◽  
Vol 39 (4) ◽  
Author(s):  
Mohazabeh Ghafuri ◽  
Bahareh Golfar ◽  
Mohsen Nosrati ◽  
Saman Hoseinkhani
Keyword(s):  
Oxidative Phosphorylation ◽  
Respiratory Chain ◽  
Energy Production ◽  
Production Efficiency ◽  
High Efficiency ◽  
Energy Transduction ◽  
Proton Pumps ◽  
Thermodynamic Evaluation ◽  
Equilibrium Thermodynamic ◽  
Atp Production

AbstractThe process of ATP production is one of the most vital processes in living cells which happens with a high efficiency. Thermodynamic evaluation of this process and the factors involved in oxidative phosphorylation can provide a valuable guide for increasing the energy production efficiency in research and industry. Although energy transduction has been studied qualitatively in several researches, there are only few brief reviews based on mathematical models on this subject. In our previous work, we suggested a mathematical model for ATP production based on non-equilibrium thermodynamic principles. In the present study, based on the new discoveries on the respiratory chain of animal mitochondria, Golfar's model has been used to generate improved results for the efficiency of oxidative phosphorylation and the rate of energy loss. The results calculated from the modified coefficients for the proton pumps of the respiratory chain enzymes are closer to the experimental results and validate the model.

scholarly journals ELECTRON MICROSCOPIC DEMONSTRATION OF ENERGY PRODUCTION AND COUPLED RESPIRATION OF IN SITU MITOCHONDRIA

1970 ◽  
Vol 18 (10) ◽  
pp. 740-745 ◽  
Author(s):  
S. KERPEL-FRONIUS ◽  
F. HAJÓS
Keyword(s):  
Respiratory Chain ◽  
Heart Muscle ◽  
Energy Production ◽  
Energy Coupling ◽  
Inhibitory Effect ◽  
Substrate Utilization ◽  
Electron Microscopic ◽  
Microscopic Demonstration ◽  
Electron Microscopic Demonstration

Respiratory-linked accumulation of Sr2+ was applied to visualize mitochondrial energy production in unfixed slices of liver, kidney and heart muscle. The reaction was dependent on the function of the respiratory chain and energy coupling as was shown by the inhibitory effect of KCN and 2,4-dinitrophenol. The electron-dense granular or needle-like reaction product was localized in the inner compartment of the swollen mitochondria. Sr2+ translocation was also utilized to detect the coupled oxidation of different respiratory substrates. The overwhelming majority of mitochondria showed, more or less, activity when malate was oxidized. In the kidney and heart muscle a few mitochondria, however, did not show succinate-supported Sr2+ accumulation. This points to the possible differences in substrate utilization of mitochondria localized in the same cells. In the liver all mitochondria exhibited marked reaction with both substrates.

Succinate, glycerophosphate and ascorbate as sources of cellular energy and as antiteratogens

Development ◽  
1970 ◽  
Vol 24 (1) ◽  
pp. 187-202
Author(s):  
Walter Landauer ◽  
Dinah Sopher
Keyword(s):  
Respiratory Chain ◽  
Energy Production ◽  
High Energy ◽  
Teratogenic Effects ◽  
Cellular Energy ◽  
Specific Affinity ◽  
Mitochondrial Energy Production ◽  
Experimental Findings ◽  
Induced Defects

Our experimental findings show that succinate and ascorbate greatly reduce the teratogenic effects of 3-acetylpyridine, 6-aminonicotinamide and sulfanilamide. Glycerophosphate led to similar alleviating results when used in combination with 3-acetylpyridine and 6-aminonicotinamide, but not with sulfanilamide. With certain other teratogens the high-energy intermediates failed to alleviate; in some instances (acetazolamide, insulin) they even led to potentiation of teratogen-induced defects. The results of our experiments demonstrate clearly that high-energy intermediates, by being fed into the respiratory chain of the mitochondria, can alleviate incidence and degree of expression of malformations produced by specific teratogens. In concert with earlier evidence on the nature of antiteratogenic compounds it can further be concluded that the particular teratogens in question exert their effects by interference with mitochondrial energy production in the tissues for which they have specific affinity.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Mitochondrial matrix calcium ions regulate energy production in myocardium: A cytochemical study

1990 ◽  
Vol 48 (2) ◽  
pp. 166-167
Author(s):  
W.A. Jacob ◽  
R. Hertsens ◽  
A. Van Bogaert ◽  
M. De Smet
Keyword(s):  
Energy Metabolism ◽  
Calcium Ions ◽  
Energy Production ◽  
Regulation Of Respiration ◽  
Free Calcium ◽  
Mitochondrial Matrix ◽  
Cytochemical Study ◽  
Nmr Techniques

In the past most studies of the control of energy metabolism focus on the role of the phosphorylation potential ATP/ADP.Pi on the regulation of respiration. Studies using NMR techniques have demonstrated that the concentrations of these compounds for oxidation phosphorylation do not change appreciably throughout the cardiac cycle and during increases in cardiac work. Hence regulation of energy production by calcium ions, present in the mitochondrial matrix, has been the object of a number of recent studies.Three exclusively intramitochondnal dehydrogenases are key enzymes for the regulation of oxidative metabolism. They are activated by calcium ions in the low micromolar range. Since, however, earlier estimates of the intramitochondnal calcium, based on equilibrium thermodynamic considerations, were in the millimolar range, a physiological correlation was not evident. The introduction of calcium-sensitive probes fura-2 and indo-1 made monitoring of free calcium during changing energy metabolism possible. These studies were performed on isolated mitochondria and extrapolation to the in vivo situation is more or less speculative.

Flavin radicals, conformational sampling and robust design principles in interprotein electron transfer: the trimethylamine dehydrogenase-electron-transferring flavoprotein complex

2004 ◽  
Vol 71 ◽  
pp. 1-14
Author(s):  
David Leys ◽  
Jaswir Basran ◽  
François Talfournier ◽  
Kamaldeep K. Chohan ◽  
Andrew W. Munro ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Kinetic Studies ◽  
Molecular Assembly ◽  
Conformational Sampling ◽  
Trimethylamine Dehydrogenase ◽  
Key Residues ◽  
Electron Transferring Flavoprotein ◽  
Electron Transfer Complex

TMADH (trimethylamine dehydrogenase) is a complex iron-sulphur flavoprotein that forms a soluble electron-transfer complex with ETF (electron-transferring flavoprotein). The mechanism of electron transfer between TMADH and ETF has been studied using stopped-flow kinetic and mutagenesis methods, and more recently by X-ray crystallography. Potentiometric methods have also been used to identify key residues involved in the stabilization of the flavin radical semiquinone species in ETF. These studies have demonstrated a key role for 'conformational sampling' in the electron-transfer complex, facilitated by two-site contact of ETF with TMADH. Exploration of three-dimensional space in the complex allows the FAD of ETF to find conformations compatible with enhanced electronic coupling with the 4Fe-4S centre of TMADH. This mechanism of electron transfer provides for a more robust and accessible design principle for interprotein electron transfer compared with simpler models that invoke the collision of redox partners followed by electron transfer. The structure of the TMADH-ETF complex confirms the role of key residues in electron transfer and molecular assembly, originally suggested from detailed kinetic studies in wild-type and mutant complexes, and from molecular modelling.

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