scholarly journals The stimulatory effects of carbon tetrachloride on peroxidative reactions in rat liver fractions in vitro. Interaction sites in the endoplasmic reticulum

1971 ◽  
Vol 123 (5) ◽  
pp. 815-821 ◽  
Author(s):  
T. F. Slater ◽  
B. C. Sawyer
Keyword(s):  
Carbon Tetrachloride ◽  
Electron Transport ◽  
Cytochrome C ◽  
Electron Transport Chain ◽  
Stimulatory Action ◽  
Interaction Sites ◽  
Nadph Cytochrome ◽  
Transport Chain ◽  
Cytochrome P 450 ◽  
Stimulation Of

1. The actions of various inhibitors of the microsomal NADPH–cytochrome P-450 electron-transport chain have been studied on the stimulatory effect of carbon tetrachloride on malonaldehyde production. 2. Carbon monoxide, p-chloromercuribenzoate, β-diethylaminoethyl-3,3′-diphenylpropyl acetate (SKF 525A) and nicotinamide did not decrease the stimulatory action of carbon tetrachloride on malonaldehyde production when present in concentrations shown to be capable of strongly inhibiting the demethylation of aminopyrine. 3. In contrast with the effects of the substances mentioned above, low concentrations of cytochrome c strongly depressed the stimulatory action of carbon tetrachloride on malonaldehyde production while increasing the endogenous rate of peroxidation. 4. Aging the microsomal suspensions at 0°C caused a rapid decrease in aminopyrine demethylation activity and in lipid peroxidation catalysed by ADP and Fe2+. The stimulation of malonaldehyde production by carbon tetrachloride was relatively unaffected, however, by aging the microsomes at 0°C for 3 days; during this period cytochrome P-450 decreased by more than 30%. 5. The conclusion is reached that the interaction between carbon tetrachloride and the NADPH–cytochrome P-450 electron-transport chain necessary for the stimulation of malonaldehyde production involves a locus near to if not identical with the NADPH–cytochrome c reductase flavoprotein.

scholarly journals Effects of L-Malate on Mitochondrial Oxidoreductases in Liver of Aged Rats

2011 ◽  
pp. 329-336 ◽  
Author(s):  
J.-L. WU ◽  
Q.-P. WU ◽  
Y.-P. PENG ◽  
J.-M. ZHANG
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Cytochrome C Oxidase ◽  
Electron Transport Chain ◽  
Nadh Dehydrogenase ◽  
Tricarboxylic Acid Cycle ◽  
Radical Scavenger ◽  
Aged Rats ◽  
Transport Chain ◽  
Nadh Cytochrome

Accumulation of oxidative damage has been implicated to be a major causative factor in the decline in physiological functions that occur during the aging process. The mitochondrial respiratory chain is a powerful source of reactive oxygen species (ROS), considered as the pathogenic agent of many diseases and aging. L-malate, a tricarboxylic acid cycle intermediate, plays an important role in transporting NADH from cytosol to mitochondria for energy production. Previous studies in our laboratory reported L-malate as a free radical scavenger in aged rats. In the present study we focused on the effect of L-malate on the activities of electron transport chain in young and aged rats. We found that mitochondrial membrane potential (MMP) and the activities of succinate dehydrogenase, NADH-cytochrome c oxidoreductase and cytochrome c oxidase in liver of aged rats were significantly decreased when compared to young control rats. Supplementation of L-malate to aged rats for 30 days slightly increased MMP and improved the activities of NADH-dehydrogenase, NADH-cytochrome c oxidoreductase and cytochrome c oxidase in liver of aged rats when compared with aged control rats. In young rats, L-malate administration increased only the activity of NADH-dehydrogenase. Our result suggested that L-malate could improve the activities of electron transport chain enzymes in aged rats

THE EFFECT OF LETHAL DOSES OF X-IRRADIATION ON THE ENZYMATIC ACTIVITY OF MITOCHONDRIAL CYTOCHROME c

1966 ◽  
Vol 44 (4) ◽  
pp. 433-448 ◽  
Author(s):  
J. F. Scaife
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Electron Transport Chain ◽  
Reductase Activity ◽  
Ehrlich Ascites Carcinoma ◽  
Whole Body ◽  
Triphenyltetrazolium Chloride ◽  
Transport Chain ◽  
Ehrlich Ascites ◽  
X Irradiation

The coupling of the tetrazolium salts triphenyltetrazolium chloride and nitro-blue tetrazolium to the electron transport chain in mitochondria of thymus, spleen, liver, kidney, and Ehrlich ascites carcinoma cells has been studied with several substrates. In experiments on succinate–triphenyltetrazolium chloride reductase activity it has been possible to demonstrate a radiation lesion in the electron transport chain of mitochondria from thymus and spleen, but not in those from other tissues. This lesion is evident 4 hours after 25 rad of whole-body irradiation, or earlier with higher doses. It is not prevented by the prior administration of aminoethylisothiouronium bromide, serotonin, vitamin K1, or vitamin E, but is reduced by anoxic conditions.Lower levels of cytochrome c are found in irradiated mitochondria isolated from thymus, and the radiation lesion is believed to be produced by loosening the binding of cytochrome c to the mitochondrial membrane after X-irradiation. Decreased levels of ATP occur in thymus, spleen, and ascites cells following irradiation.

scholarly journals Cytochrome c is phosphorylated by AMP kinase in mammalian kidney, leading to controlled electron transport chain flux

2016 ◽  
Vol 1857 ◽  
pp. e78
Author(s):  
Maik Hüttemann ◽  
Gargi Mahapatra ◽  
Ashwathy Varughese ◽  
Qinqin Ji ◽  
Icksoo Lee ◽  
...  
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Electron Transport Chain ◽  
Amp Kinase ◽  
Mammalian Kidney ◽  
Transport Chain

scholarly journals Oxidative and non-oxidative mechanisms in the inactivation of cardiac mitochondrial electron transport chain components by doxorubicin

1989 ◽  
Vol 259 (1) ◽  
pp. 181-189 ◽  
Author(s):  
O Marcillat ◽  
Y Zhang ◽  
K J A Davies
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Oxidative Damage ◽  
Cytochrome C Oxidase ◽  
Electron Transport Chain ◽  
Nadh Dehydrogenase ◽  
Nadh Oxidase ◽  
Redox Cycling ◽  
Oxidative Inactivation ◽  
Transport Chain

The quinonoid anthracycline, doxorubicin (Adriamycin) is a potent anti-neoplastic agent whose clinical use is limited by severe cardiotoxicity. Mitochondrial damage is a major component of this cardiotoxicity, and rival oxidative and non-oxidative mechanisms for inactivation of the electron transport chain have been proposed. Using bovine heart submitochondrial preparations (SMP) we have now found that both oxidative and non-oxidative mechanisms occur in vitro, depending solely on the concentration of doxorubicin employed. Redox cycling of doxorubicin by Complex I of the respiratory chain (which generates doxorubicin semiquinone radicals, O2-, H2O2, and .OH) caused a 70% decrease in the Vmax. for NADH dehydrogenase during 15 min incubation of SMP, and an 80% decrease in NADH oxidase activity after 2 h incubation. This inactivation required only 25-50 microM-doxorubicin and represents true oxidative damage, since both NADH (for doxorubicin redox cycling) and oxygen were obligatory participants. The damage appears localized between the NADH dehydrogenase flavin (site of doxorubicin reduction) and iron-sulphur centre N-1. Succinate dehydrogenase, succinate oxidase, and cytochrome c oxidase activities were strongly inhibited by higher doxorubicin concentrations, but this phenomenon did not involve doxorubicin redox cycling (no NADH or oxygen requirement). Doxorubicin concentrations of 0.5 mM were required for 50% decreases in these activities, except for cytochrome c oxidase which was only 30% inhibited following incubation with even 1.0 mM-doxorubicin. Our results indicate that low concentrations of doxorubicin (50 microM or less) can catalyse a site-specific oxidative damage to the NADH oxidation pathway. In contrast, ten-fold higher doxorubicin concentrations (or more) are required for non-oxidative inactivation of the electron transport chain; probably via binding to cardiolipin and/or generalized membrane chaotropic effects. The development of agents to block doxorubicin toxicity in vivo will clearly require detailed clinical studies of doxorubicin uptake in the heart.

scholarly journals The microbial metabolism of C1 compounds. The electron-transport chain of Pseudomonas AM1

1975 ◽  
Vol 152 (2) ◽  
pp. 349-356 ◽  
Author(s):  
David Widdowson ◽  
Christopher Anthony
Keyword(s):  
Electron Transport ◽  
Cytochrome C ◽  
Redox Potential ◽  
Molecular Oxygen ◽  
Cytochrome B ◽  
Electron Transport Chain ◽  
Difference Spectrum ◽  
Reduced Form ◽  
Transport Chain ◽  
Oxidation By Molecular Oxygen

Pseudomonas AM1, Hyphomicrobium X and Pseudomonas MS all contain cytochrome a/a3 and a b-type cytochrome able to react with CO. Pseudomonas AM1 and Hyphomicrobium X also have a CO-binding cytochrome c. The purified cytochrome c (redox potential 0.26V) of Pseudomonas AM1 was not susceptible to oxidation by molecular oxygen. CO reacted slowly with the reduced form giving a CO difference spectrum with a peak at 412nm and troughs at 420nm and 550nm. Similar results were obtained with the cytochrome c of Hyphomicrobium (aerobically grown or anaerobically grown with nitrate) and with that of Pseudomonas extorquens. The results given in the present paper are incompatible with an oxygenase or oxidase function for the soluble cytochrome c of methylotrophs. Studies with whole cells of Pseudomonas AM1 and a cytochrome c-deficient mutant have demonstrated that cytochrome b (redox potential 0.009V) is the first cytochrome in the electron-transport chain for oxidation of all substrates except methanol (and ethanol) whose oxidation does not involve this cytochrome. All substrates are usually oxidized by way of cytochrome c and cytochrome oxidase (cytochrome a/a3), but there is an alternative route for the reduction of cytochrome a/a3 in the mutant lacking cytochrome c. Results of experiments on cyanide inhibition of respiration and cytochrome oxidation support the suggestion that the susceptibility of cytochrome b to oxidation by molecular oxygen (reflected in its ability to react with CO) is probably irrelevant to the normal physiology of Pseudomonas AM1.

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