scholarly journals Major changes in complex I activity in mitochondria from aged rats may not be detected by direct assay of NADH:coenzyme Q reductase

1995 ◽  
Vol 311 (1) ◽  
pp. 105-109 ◽  
Author(s):  
M L Genova ◽  
C Castelluccio ◽  
R Fato ◽  
G Parenti Castelli ◽  
M Merlo Pich ◽  
...  
Keyword(s):  
Oxidase Activity ◽  
Complex I ◽  
Nadh Oxidase ◽  
Reductase Activity ◽  
Coenzyme Q ◽  
Nadh Oxidation ◽  
Aged Rats ◽  
Nadh Oxidase Activity ◽  
Complex I Activity ◽  
The Relationship

We have investigated the respiratory activities and the concentrations of respiratory chain components of mitochondria isolated from the livers and hearts of two groups of rats aged 6 and 24 months respectively. In comparison with the adult controls (6 months), in aged rats there was a decline in total aerobic NADH oxidation in both tissues; only minor (non-significant) changes, however, were found in NADH:coenzyme Q reductase and cytochrome oxidase activities, and there was no change in ubiquinol-cytochrome c reductase activity. The coenzyme Q levels were slightly decreased in mitochondria from both organs of aged rats. The lowered NADH oxidase activity is not due to the slight decrease observed in the coenzyme Q levels, but is the result of decreased Complex I activity. Since the assay of NADH:coenzyme Q reductase requires quinone analogues, none of which can evoke its maximal turnover [Estornell, Fato, Pallotti and Lenaz (1993) FEBS Lett. 332, 127-131], its activity has been calculated indirectly by taking advantage of the relationship that exists between NADH oxidation and ubiquinol oxidation through the coenzyme Q pool. The results, expressed in this way, show a drastic loss of activity of Complex I in both the heart and the liver of aged animals in comparison with adult controls.

scholarly journals The NADH oxidase system (external) of muscle mitochondria and its role in the oxidation of cytoplasmic NADH

1985 ◽  
Vol 229 (3) ◽  
pp. 631-641 ◽  
Author(s):  
U F Rasmussen ◽  
H N Rasmussen
Keyword(s):  
Oxidase Activity ◽  
Nadh Oxidase ◽  
Specific Activity ◽  
Reductase Activity ◽  
Heart Mitochondria ◽  
Freezing And Thawing ◽  
Oxidase System ◽  
Muscle Mitochondria ◽  
Nadh Oxidase Activity

An exo-NADH oxidase system [NADH oxidase system (external)], effecting intact-mitochondrial oxidation of added NADH, was studied in pigeon heart mitochondria. Breast muscle mitochondria showed an equal specific activity of the system. The exo-NADH oxidase activity (200 micron mol of NADH/min per g of protein) equalled two-thirds of the State-3 respiratory activity with malate + pyruvate or one-seventh of the total NADH oxidase activity of heart mitochondria. The activity was not caused by use of proteinase in the preparation procedure and all measured parameters were very reproducible from preparation to preparation. The activity is therefore most likely not due to preparation artefacts. The exo-NADH oxidase system is present in all mitochondria in the preparation and is not confined to a subpopulation. The system reduced all cytochrome anaerobically and direct interaction with all cytochrome oxidase was demonstrated by interdependent cyanide inhibition. The exo-NADH oxidase system seems to be located at the outer surface of the mitochondrial inner membrane because, for instance, only this system was rapidly inhibited by rotenone, and ferricyanide could act as acceptor in the rotenone-inhibited system (reductase activity = 20 times oxidase activity). In the presence of antimycin, added NADH reduced only a part of the b-cytochromes. Freezing and thawing the mitochondria, one of the methods used for making them permeable to NADH, destroyed this functional compartmentation. The characteristics of the exo-NADH oxidase system and the malate-aspartate shuttle are compared and the evidence for the shuttle's function in heart in vivo is re-evaluated. It is proposed that oxidation of cytoplasmic NADH in red muscles primarily is effected by the exo-NADH oxidase system.

scholarly journals Inhibitory effect of palmitate on the mitochondrial NADH:ubiquinone oxidoreductase (complex I) as related to the active–de-active enzyme transition

2005 ◽  
Vol 387 (3) ◽  
pp. 677-683 ◽  
Author(s):  
Maria V. LOSKOVICH ◽  
Vera G. GRIVENNIKOVA ◽  
Gary CECCHINI ◽  
Andrei D. VINOGRADOV
Keyword(s):  
Oxidase Activity ◽  
Complex I ◽  
Nadh Oxidase ◽  
Reductase Activity ◽  
Residual Activity ◽  
Quinone Reductase ◽  
Enzyme Concentration ◽  
Complete Relief ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Activated Complex

Palmitate rapidly and reversibly inhibits the uncoupled NADH oxidase activity catalysed by activated complex I in inside-out bovine heart submitochondrial particles (IC50 extrapolated to zero enzyme concentration is equal to 9 μM at 25 °C, pH 8.0). The NADH:hexa-ammineruthenium reductase activity of complex I is insensitive to palmitate. Partial (∼50%) inhibition of the NADH:external quinone reductase activity is seen at saturating palmitate concentration and the residual activity is fully sensitive to piericidin. The uncoupled succinate oxidase activity is considerably less sensitive to palmitate. Only a slight stimulation of tightly coupled respiration with NADH as the substrate is seen at optimal palmitate concentrations, whereas complete relief of the respiratory control is observed with succinate as the substrate. Palmitate prevents the turnover-induced activation of the de-activated complex I (IC50 extrapolated to zero enzyme concentration is equal to 3 μM at 25 °C, pH 8.0). The mode of action of palmitate on the NADH oxidase is qualitatively temperature-dependent. Rapid and reversible inhibition of the complex I catalytic activity and its de-active to active state transition are seen at 25 °C, whereas the time-dependent irreversible inactivation of the NADH oxidase proceeds at 37 °C. Palmitate drastically increases the rate of spontaneous de-activation of complex I in the absence of NADH. Taken together, these results suggest that free fatty acids act as specific complex I-directed inhibitors; at a physiologically relevant temperature (37 °C), their inhibitory effects on mitochondrial NADH oxidation is due to perturbation of the pseudo-reversible active–de-active complex I transition.

scholarly journals Structural and Kinetic Characterization of Hyperthermophilic NADH-Dependent Persulfide Reductase from Archaeoglobus fulgidus

Archaea ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Sherwin Shabdar ◽  
Bukuru Anaclet ◽  
Ana Garcia Castineiras ◽  
Neyissa Desir ◽  
Nicholas Choe ◽  
...  
Keyword(s):  
Nadh Oxidase ◽  
Reductase Activity ◽  
Sulfur Metabolism ◽  
Archaeoglobus Fulgidus ◽  
Bacterial Enzymes ◽  
Detectable Activity ◽  
Metabolic Role ◽  
Nadh Oxidase Activity

NADH-dependent persulfide reductase (Npsr) has been proposed to facilitate dissimilatory sulfur respiration by reducing persulfide or sulfane sulfur-containing substrates to H2S. The presence of this gene in the sulfate and thiosulfate-reducing Archaeoglobus fulgidus DSM 4304 and other hyperthermophilic Archaeoglobales appears anomalous, as A. fulgidus is unable to respire S0 and grow in the presence of elemental sulfur. To assess the role of Npsr in the sulfur metabolism of A. fulgidus DSM 4304, the Npsr from A. fulgidus was characterized. AfNpsr is specific for persulfide and polysulfide as substrates in the oxidative half-reaction, exhibiting k cat / K m on the order of 104 M-1 s-1, which is similar to the kinetic parameters observed for hyperthermophilic CoA persulfide reductases. In contrast to the bacterial Npsr, AfNpsr exhibits low disulfide reductase activity with DTNB; however, similar to the bacterial enzymes, it does not show detectable activity with CoA-disulfide, oxidized glutathione, or cystine. The 3.1 Å X-ray structure of AfNpsr reveals access to the tightly bound catalytic CoA, and the active site Cys 42 is restricted by a flexible loop (residues 60-66) that is not seen in the bacterial homologs from Shewanella loihica PV-4 and Bacillus anthracis. Unlike the bacterial enzymes, AfNpsr exhibits NADH oxidase activity and also shows no detectable activity with NADPH. Models suggest steric and electrostatic repulsions of the NADPH 2 ′ -phosphate account for the strong preference for NADH. The presence of Npsr in the nonsulfur-reducing A. fulgidus suggests that the enzyme may offer some protection against S0 or serve in another metabolic role that has yet to be identified.

scholarly journals NADH Oxidase Activity of Mitochondrial Apoptosis-inducing Factor

2001 ◽  
Vol 276 (19) ◽  
pp. 16391-16398 ◽  
Author(s):  
M. Dolores Miramar ◽  
Paola Costantini ◽  
Luigi Ravagnan ◽  
Ligia M. Saraiva ◽  
Delphine Haouzi ◽  
...  
Keyword(s):  
Oxidase Activity ◽  
Nadh Oxidase ◽  
Mitochondrial Apoptosis ◽  
Nadh Oxidase Activity ◽  
Apoptosis Inducing Factor

Effects of Vanadate on the Molybdoproteins Xanthine Oxidase and Nitrate Reductase: Kinetic Evidence for Multiple Site Interaction

1980 ◽  
Vol 35 (9-10) ◽  
pp. 702-707 ◽  
Author(s):  
Candadai S. Ramadoss
Keyword(s):  
Catalytic Activity ◽  
Nitrate Reductase ◽  
Xanthine Oxidase ◽  
Oxidase Activity ◽  
Metal Ion ◽  
Nadh Oxidase ◽  
Multiple Site ◽  
Vanadate Inhibition ◽  
Nadh Oxidase Activity

Abstract The inhibition of the activity of xanthine oxidase by vanadate was strikingly similar to vanadate inhibition of another molybdoprotein nitrate reductase. Although the main catalytic activity of both enzymes was inhibited, the partial NADH oxidase activity associated with these enzymes was stimulated several fold. It appears that the metal ion binds at multiple site in both enzymes. In the absence of any enzymes a combination of vanadium (V) and molybdenum (V) in air was found to oxide NADH rapidly.

scholarly journals Identification of the NADH-oxidase gene in Trichomonas vaginalis

2019 ◽  
Vol 119 (2) ◽  
pp. 683-686 ◽  
Author(s):  
Aline Lamien-Meda ◽  
David Leitsch
Keyword(s):  
Oxidase Activity ◽  
Trichomonas Vaginalis ◽  
Nadh Oxidase ◽  
Flavin Mononucleotide ◽  
Flavin Reductase ◽  
Oxidase Gene ◽  
Reading Frame ◽  
Sexually Transmitted ◽  
Cell Extracts ◽  
Nadh Oxidase Activity

AbstractThe microaerophilic human parasite Trichomonas vaginalis causes infections in the urogenital tract and is one of the most often sexually transmitted pathogens worldwide. Due to its anaerobic metabolism, it has to quickly remove intracellular oxygen in order to avoid deactivation of essential metabolic enzymes such as oxygen-sensitive pyruvate:ferredoxin oxidoreductase (PFOR). Two major enzyme activities which are responsible for the removal, i.e. reduction, of molecular oxygen have been identified in T. vaginalis flavin reductase, formerly designated NADPH oxidase, which indirectly reduces oxygen to hydrogen peroxide via flavin mononucleotide (FMN), and NADH oxidase which reduces oxygen to water. Flavin reductase has been identified and characterized at the gene level as well as enzymatically, but NADH oxidase has so far only been characterized enzymatically with enzyme isolated from T. vaginalis cell extracts. In this study, we identified NADH oxidase by mass spectrometry after isolation of the enzyme from gel bands positively staining for NADH oxidase activity. In strain C1 (ATCC 30001) which is known to lack NADH oxidase activity completely, the NADH oxidase gene has a deletion at position 1540 of the open reading frame leading to a frame shift and, as a consequence, to premature termination of the encoded polypeptide.

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