Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:1.9.3.1 (cytochrome oxidase)
8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The biochemical characteristics of the electron transfer chain are evaluated in purified non-synaptic ("free") mitochondria from the forebrain of 60-week-old rats weekly subjected to peroxidative stress (once, twice, or three times) by the electrophilic prooxidant 2-cyclohexene-1-one. The following parameters are evaluated: (a) content of respiratory components, namely ubiquinone, cytochrome b, cytochrome c1, cytochrome c; (b) specific activity of enzymes, namely citrate synthase, succinate dehydrogenase, rotenone-sensitive NADH: cytochrome c reductase, cytochrome oxidase; (c) concentration of reduced glutathione (GSH). Before the first peroxidative stress induction, the rats are administered for 8 weeks by intraperitoneal injection of vehicle, papaverine, delta-yohimbine, almitrine or hopanthenate. The rats are treated also during the week(s) before the second or third peroxidative stress. The cerebral peroxidative stress induces: (a) initially, a decrease in brain GSH concentration concomitant with a decrease in the mitochondrial activity of cytochrome oxidase of aa3-type (complex IV), without changes in ubiquinone and cytochrome b populations; (b) subsequently, an alteration in the transfer molecule cytochrome c and, finally, in rotenone-sensitive NADH-cytochrome c reductase (complex I) and succinate dehydrogenase (complex II). The selective sensitivity of the chain components to peroxidative stress is supported by the effects of the concomitant subchronic treatment with agents acting at different biochemical steps. In fact, almitrine sets limits to its effects at cytochrome c content and aa3-type cytochrome oxidase activity, while delta-yohimbine sets limits to its effects at the level of tricarboxylic acid cycle (citrate synthase) and/or of intermediary between tricarboxylic acid cycle and complex II (succinate dehydrogenase).(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Sequential damage in mitochondrial complexes by peroxidative stress. 166 94

The maximum rates (Vmax) of some mitochondrial enzyme activities related to energy transduction (citrate synthase, malate dehydrogenase, NADH cytochrome c reductase, cytochrome oxidase) and amino acid metabolism (glutamate dehydrogenase) were evaluated in non-synaptic (free) and synaptic mitochondria from rat hippocampus and striatum. Three types of mitochondria were isolated from control rats aged 4, 8, 12, 16, 20 and 24 months and treated ones with L-acetylcarnitine (100 mg.kg-1, i.p., 60 min). Enzyme activities of non-synaptic and synaptic mitochondria are different in hippocampus and striatum, confirming that a different metabolic machinery exists in various types of brain mitochondria. During aging, enzyme activities behave quite similarly in both areas. In vivo administration of L-acetylcarnitine decreased the enzyme activities related to Krebs' cycle mainly of synaptic mitochondria, suggesting a specific subcellular trigger site of action. The drug increased cytochrome oxidase activity of synaptic and non-synaptic mitochondria, indicating the specificity of molecular interaction with this enzyme.
...
PMID:Action of L-acetylcarnitine on different cerebral mitochondrial populations from hippocampus and striatum during aging. 166 44

The maximal rate (Vmax) of some mitochondrial enzyme activities related to energy transduction (citrate synthase, alpha-ketoglutarate dehydrogenase, malate dehydrogenase, succinate dehydrogenase, NADH-cytochrome c reductase, cytochrome oxidase) and amino acid metabolism (glutamate dehydrogenase, glutamate-pyruvate transaminase and glutamate-oxaloacetate transaminase) are evaluated in non synaptic ("free") and intrasynaptic mitochondria from brain hippocampus. The different mitochondrial populations were isolated from rat subjected to single i.p. treatment with saline solution, almitrine (30 mg/kg) and delta-yohimbine (10 mg/kg). In control rats, the mitochondrial populations exhibit different enzymatic patterns. Acute treatment with almitrine decreases cytochrome oxidase activity in intra-synaptic mitochondria, while acute treatment with delta-yohimbine decreases succinate dehydrogenase activity in both types of free and intra-synaptic mitochondria. NADH-cytochrome c reductase activity is also decreased by acute treatment with almitrine ("free" and "synaptic" mitochondria) and delta-yohimbine (synaptic mitochondria only).
...
PMID:Factors involved in drug interference on enzyme activities of three mitochondrial populations from rat hippocampus. 180 34

Two cationic, lipophilic laser dyes, 1,1',3,3,3',3'-hexamethylindodicarbocyanine iodide (HIDC) and 1,1',3,3,3',3'-hexamethylindotricarbocyanine iodide (HITC), inhibit bovine heart mitochondrial and Paracoccus denitrificans NADH oxidase activities. The mitochondrial I50 values were 0.5 microM (HIDC) and 1.2 microM (HITC), and the P. denitrificans I50 values 1.2 microM (HIDC) and 1.5 microM (HITC). Neither succinate nor cytochrome oxidase (EC 1.9.3.1) activities were inhibited significantly by either compound, localizing the site of inhibition to the segment of each electron transport chain between NADH and ubiquinone. With submitochrondrial particles (SMP), NADH-dependent reduction of menadione, duroquinone and coenzyme Q1 was inhibited markedly (HIDC was the more potent inhibitor). Using purified complex I, only NADH-dependent reduction of duroquinone and coenzyme Q1 was inhibited markedly (HIDC was the more potent inhibitor) and reduction of menadione was inhibited slightly. With P. denitrificans membrane vesicles, NADH-dependent reduction of menadione, juglone, and coenzyme Q1 was inhibited slightly and duroquinone reduction was inhibited markedly. Membrane-dependent interactions appear to be involved, since the compounds were more inhibitory with membrane preparations than with complex I. The mechanism of inhibition (except for the HIDC effect on coenzyme Q1 reduction with P. denitrificans) appeared to be through the interaction of dye with the rotenone site on NADH-ubiquinone reductase (EC 1.6.99.3), since rotenone-insensitive preparations of complex I and P. denitrificans membrane vesicles were also insensitive to HIDC and HITC inhibition.
...
PMID:Inhibitory effects of two structurally related carbocyanine laser dyes on the activity of bovine heart mitochondrial and Paracoccus denitrificans NADH-ubiquinone reductase. Evidence for a rotenone-type mechanism. 190 Jan 56

The effects of arachidonic acid on the enzyme complexes in the electron transport system were investigated using submitochondrial particles from rat brain. Arachidonic acid irreversibly inhibited NADH-CoQ oxidoreductase (complex I) activity, but had no effect on the activities of succinate-CoQ oxidoreductase (complex II), CoQH2-cytochrome c oxidoreductase (complex III), cytochrome c oxidase (complex IV), ATPase (complex V), glutamate dehydrogenase, and malate dehydrogenase up to 50 microM. The inhibition was dose-dependent with an IC50 value of 110 nmol/mg protein. The Lineweaver-Burk plot revealed that the inhibition by arachidonic acid was noncompetitive against CoQ with a Ki value of 33 microM and uncompetitive against NADH with a Ki value of 22 microM.
...
PMID:Selective inhibition of NADH-CoQ oxidoreductase (complex I) of rat brain mitochondria by arachidonic acid. 190 30

The effects of butylated hydroxyanisole (BHA), a commonly used food antioxidant, on oxygen consumption, ATPase activity, and the redox state of some electron carriers of rat liver mitochondria have been studied. It was observed that BHA slightly stimulated state 4 respiration but strongly inhibited ADP- and uncoupler-stimulated respiration on NAD(+)- and FAD-linked substrates. ATPase activity and vectorial H+ ejection were affected only slightly by BHA, suggesting that BHA predominantly inhibits mitochondrial electron flow. Experiments to determine its site of action showed that BHA did not noticeably affect electron flow through cytochrome oxidase; in contrast, NADH:duroquinone reductase activity and electron flow through ubiquinone-cytochrome b-cytochrome c complex were inhibited strongly because the oxidation of duroquinol was affected markedly. The BHA block of electron transport was bypassed by both N,N,N',N'-tetramethyl-p-phenylenediamine and 2,6-dichlorophenolindophenol. Also, the presence of BHA changed the redox state of cytochrome b and c1 to a more oxidized level. These observations suggest that electron transport is inhibited by BHA at the NADH-ubiquinone and at the ubiquinone-cytochrome b levels. From Hill plots, it is clear that more than one binding site is involved in complete inhibition; in addition, available evidence suggests that there may be two sites at the substrate side of ubiquinone and another two sites at the oxygen side of ubiquinone. Consequently, mitochondrial ATP synthesis would be interrupted. This event could be related to the toxicity of BHA.
...
PMID:Effect of butylated hydroxyanisole on electron transport in rat liver mitochondria. 214 54

Administration of sodium perchlorate to rats for 45 days leads to decreased activities of citric acid cycle enzymes. The oxidation of succinate both in state 3 and state 4 conditions and endogenous ATP content of mitochondria decreased during perchlorate toxicity. The significant decrease in cytochrome aa3 in perchlorate-treated rats may be one of the prime factors involved in the decreased rate of respiration. The permeability of mitochondria of perchlorate-treated rats is altered as indicated by increased oxidation of NADH and low respiratory control ratio (RCR).
...
PMID:Effect of perchlorate on mitochondrial function. 216 Apr 26

The possible role of hepatic mitochondrial function and lysosomal enzyme activity in ethanol-enhanced aflatoxin B1 (AFB1) hepatotoxicity was studied in male rats. Hepatic ATP content was significantly decreased in rats treated with ethanol (4.0 g/kg body wt.) and AFB1 (2.0 mg/kg body wt.) compared with rats treated with AFB1 alone at 12-72 h after AFB1 administration. The decrease in hepatic ATP content was due to the decrease in the activity of NADH-cytochrome c reductase whereas cytochrome oxidase activity did not differ in rats treated with ethanol and AFB1 when compared to AFB1 alone. Total and free activities of hepatic lysosomal enzymes (glucuronidase, arylsulfatase and acid phosphatase) were significantly increased in rats treated with ethanol and AFB1 at 24-36 h after AFB1 administration when compared to AFB1 alone. The increase in hepatic lysosomal enzyme activities correlated well with the increase in the lipid peroxide level of lysosomes in rats treated with ethanol and AFB1. These findings indicate that the decrease in hepatic mitochondrial respiratory enzyme activities and the increase in lipid peroxide level of lysosomes might lead to a decrease in hepatic ATP content, and that the increase in the activities of hepatic lysosomal enzymes, respectively, enhance the AFB1 hepatotoxicity of ethanol.
...
PMID:Hepatic mitochondrial function and lysosomal enzyme activity in ethanol-potentiated aflatoxin B1 hepatotoxicity. 216 42

Bovine heart submitochondrial particles (SMP) were exposed to continuous fluxes of hydroxyl radical (.OH) alone, superoxide anion radical (O2-) alone, or mixtures of .OH and O2-, by gamma radiolysis in the presence of 100% N2O (.OH exposure), 100% O2 + formate (O2- exposure), or 100% O2 alone (.OH + O2- exposure). Hydrogen peroxide effects were studied by addition of pure H2O2. NADH dehydrogenase, NADH oxidase, succinate dehydrogenase, succinate oxidase, and ATPase activities (Vmax) were rapidly inactivated by .OH (10% inactivation at 15-40 nmol of .OH/mg of SMP protein, 50-90% inactivation at 600 nmol of .OH/mg of SMP protein) and by .OH + O2- (10% inactivation at 20-80 nmol of .OH + O2-/mg of SMP protein, 45-75% inactivation at 600 nmol of .OH + O2-/mg of SMP protein). Importantly, O2- was a highly efficient inactivator of NADH dehydrogenase, NADH oxidase, and ATPase (10% inactivation at 20-50 nmol of O2-/mg of SMP protein, 40% inactivation at 600 nmol of O2-/mg of SMP protein), a mildly efficient inactivator of succinate dehydrogenase (10% inactivation at 150 nmol of O2-/mg of SMP protein, 30% inactivation at 600 nmol of O2-/mg of SMP protein), and a poor inactivator of succinate oxidase (less than 10% inactivation at 600 nmol of O2-/mg of SMP protein). H2O2 partially inactivated NADH dehydrogenase, NADH oxidase, and cytochrome oxidase, but even 10% loss of these activities required at least 500-600 nmol of H2O2/mg of SMP protein. Cytochrome oxidase activity (oxygen consumption supported by ascorbate + N,N,N',N'-tetramethyl-p-phenylenediamine) was remarkably resistant to oxidative inactivation, with less than 20% loss of activity evident even at .OH, O2-, OH + O2-, or H2O2 concentrations of 600 nmol/mg of SMP protein. Cytochrome c oxidase activity, however (oxidation of, added, ferrocytochrome c), exhibited more than a 40% inactivation at 600 nmol of .OH/mg of SMP protein. The .OH-dependent inactivations reported above were largely inhibitable by the .OH scavenger mannitol. In contrast, the O2(-)-dependent inactivations were inhibited by active superoxide dismutase, but not by denatured superoxide dismutase or catalase. Membrane lipid peroxidation was evident with .OH exposure but could be prevented by various lipid-soluble antioxidants which did not protect enzymatic activities at all.(ABSTRACT TRUNCATED AT 400 WORDS)
...
PMID:The oxidative inactivation of mitochondrial electron transport chain components and ATPase. 216 88

Brain mitochondrial enzyme activities were examined in 15-day-old suckling mice which were daily injected with D-penicillamine (DP), a chelating agent of copper. Newborn mice treated with DP (1 g/kg/day) showed retarded weight gain, hyperelasticity of skin, and a bizarre forelimb posture with subcutaneous edema on experimental day (ED) 7. Paraparesis or dragging of the hindlimbs was observed by ED 15. Brain copper contents of DP-treated mice decreased to 34% of the controls of ED 15. Cytochrome c oxidase activity (complex IV) in the brain showed 51% decrease of the controls, on the contrary, rotenone-sensitive NADH cytochrome c reductase (complex I + III) and succinate cytochrome c reductase (complex II + III) were normal. Histochemistry of cytochrome c oxidase in the cerebellum of DP-treated mice disclosed diffuse reduction of staining, especially in Purkinje cells. These data show that DP-induced copper deficiency in the brain subsequently disturbs mitochondrial electron transport system, selectively cytochrome c oxidase activity. This seems to be a useful animal model not only for Menkes' kinky hair disease but also for mitochondrial encephalomyopathy.
...
PMID:D-penicillamine-induced copper deficiency in suckling mice: neurological abnormalities and brain mitochondrial enzyme activities. 217 57


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---