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

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

The influence of sodium nitroprusside (SNP) on mitochondrial respiration was examined in rat liver mitochondria. The addition of SNP 1 mmol litre-1 during state 3 respiration inhibited the oxygen uptake by 63.4%. A mixture of SNP 1 mmol litre-1 and glutathione (GSH) 1 mmol litre-1 inhibited the oxygen uptake more markedly (by 75.9%). The cyanide concentrations were 0.01 mmol litre-1 with SNP alone and 0.15 mmol litre-1 with the mixture of SNP and GSH. Cyanide production from SNP in the presence of various reducing agents was studied in potassium phosphate 0.1 mol litre-1 buffer solution (pH 7.4) incubated at 37 degrees C. Cyanide was liberated markedly from SNP in the presence of GSH or ascorbate. Less cyanide was produced in the presence of NADH or NADPH. The rate of production of cyanide was dependent entirely upon the concentration of each reducing agent added. No cyanide was liberated when sodium dithionite or the oxidized forms of GSH, NAD or NADP were used. It was concluded that SNP is degradated to cyanide by a hydrogen donor and that the cyanide liberated in this manner inhibits the cytochrome oxidase activity of mitochondria in vivo.
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PMID:Inhibition of mitochondrial respiration by sodium nitroprusside and the mechanism of cyanide liberation. 58

The tissutal concentrations of reduced glutathione (GSH) and the contents of some key components in the electron transfer chain (namely ubiquinone, cytochromes b, c1, c, and aa3) of the intraterminal mitochondria are measured in the forebrains from 20-, 60-, or 100-week-old Wistar rats. Moreover, in 60-week-old rats, the biochemical analyses are performed also 18 h after the induction of a peroxidative stress by cyclohexene-1-one. The rats have been i.p. pretreated for 8 weeks (7 days/week) with agents acting on macrocirculation (papaverine), carbohydrate metabolism (hopanthenate), lipid metabolism (phosphatidylcholine), energy transduction (theniloxazine), and dopaminergic system (dihydroergocriptine). Brain aging is characterized by the decrease in both GSH and mitochondrial cytochrome aa3, without changes in ubiquinone and cytochrome b populations. In the same way, the peroxidative stress induced by cyclohexene-1-one causes both a GSH depletion and an imbalance among the concentrations of the mitochondrial electron transfer carriers. Only cytochrome aa3 retains all the partially-reduced oxygen intermediates tightly bound to its active sites. Therefore, it is possible to hypothesize that an electron leakage at the level of the auto-oxidizing chain components (i.e., cytochrome b and ubiquinone populations) increases the release of activated oxygen species (superoxide radical, hydroxyl radical). The treatment with the quoted pharmacological tools suggests that GSH and mitochondrial electron transfer carriers are functionally linked, but not interdependent one another.
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PMID:The mitochondrial electron transfer alteration as a factor involved in the brain aging. 132 Jul 45

The five major antioxidants enzymes, cytochrome oxidase (COX), GSH, and GSSG, and endogenous and in vitro stimulated lipid peroxidation (TBA-RS) were assayed in the lung of old (28 months) and young (9 months) adult rats due to the almost total absence of data of this kind in this tissue, which is normally exposed to relatively high pO2 throughout life. Catalase, selenium (Se)-dependent GSH peroxidase (GPx), GSH reductase, GSH, GSSG, GSSG/GSH, and in vivo and in vitro TBA-RS showed similar values in old and young animals. The decrease observed for non Se-dependent GPx disappeared when the values were expressed in relation to COX activity. Only superoxide dismutase showed a clear decrease when referred both to protein and COX activity. These results suggest that lung aging is not accelerated in old age due to a decrease in the antioxidant capacity of the tissue. Nevertheless, they are compatible with a continuous damage of the lung tissue by free radicals throughout the life span.
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PMID:Aging and lung antioxidant enzymes, glutathione, and lipid peroxidation in the rat. 164 50

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)
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PMID:Sequential damage in mitochondrial complexes by peroxidative stress. 166 94

Cyclohexene-1-one and cycloheptene-1-one cause a severe age-related depletion of reduced glutathione (GSH) in the forebrain of 5- or 15- or 25-month-old rats. Chronic pretreatment with phosphatidylcholine partially inhibits the GSH depletion in old forebrains by the prooxidants tested, suggesting that in aged animals alterations in mitochondrial inner membrane phospholipid composition and/or cytochrome oxidase activity might play a role in oxygen free-radical production.
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PMID:Age-related acute depletion of cerebral glutathione by peroxidative stress. 166 89

Old rats (28 months), when compared with young adults (9 months), did not show differences in activities of superoxide dismutase (SOD) or selenium-dependent and -independent glutathione peroxidases (GPx), or in levels of GSH, GSSG, GSSG/GSH and endogenous peroxidation in liver and brain. Rates of stimulated peroxidation in vitro were decreased in the livers of old rats. Old animals showed decreased levels of hepatic catalase and glutathione reductase. Nevertheless, when enzyme activities were referred to cytochrome oxidase activity these decreases disappeared, and GPx and SOD (brain) were even increased in old rats.
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PMID:Anti-oxidant defences and peroxidation in liver and brain of aged rats. 217 82

1. A number of dietary sugars are known to mediate the effects of copper deficiency. The effects of lactose (compared with sucrose) and a dietary Cu deficiency on hepatic and cardiac antioxidant enzyme activities and tissue mineral element status were investigated in the rat. 2. Groups (n 6) of male weanling Wistar rats were provided ad lib. with deionized water and diets containing sucrose (580 g/kg) or sucrose and lactose (387 g/kg and 193 g/kg respectively) with either control (12.0 mg/kg) or deficient (1.5 mg/kg) quantities of Cu for 77 d. 3. Animals consuming the low-Cu diets exhibited significantly decreased tissue Cu levels (P less than 0.01), hepatic and cardiac cytochrome c oxidase (EC 1.9.3.1, CCO) activities (P less than 0.01 and P less than 0.001 respectively) and hepatic Cu-zinc superoxide dismutase (EC 1.15.1.1, CuZnSOD) activity (P less than 0.05). The low-Cu diets also significantly decreased cardiac manganese superoxide dismutase (EC 1.15.1.1, MnSOD), catalase (EC 1.11.1.6) and glutathione peroxidase (EC 1.11.1.9, GSH-Px) activities (P less than 0.01, P less than 0.05 and P less than 0.001 respectively). 4. Hepatic Mn was significantly increased in both lactose-fed (P less than 0.001) and Cu-deficient (P less than 0.01) animals. These increases were unrelated to hepatic MnSOD activity. Cardiac Zn was significantly (P less than 0.01) increased in Cu-deficient animals. 5. Lactose feeding resulted in significantly increased cardiac CCO activity (P less than 0.001) but significantly decreased hepatic CuZnSOD (P less than 0.05), catalase (P less than 0.01) and GSH-Px (P less than 0.001) activities. 6. The activities of lactose dehydrogenase (EC 1.1.1.27, LDH) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49, G6PDH) were found to be significantly (P less than 0.05 and P less than 0.01 respectively) increased in Cu-deficient animals and G6PDH activity was significantly (P less than 0.01) decreased as a result of lactose consumption. 7. The observed changes in antioxidant enzyme activities associated with both Cu deficieny and lactose consumption may have important implications for the development of free radical mediated cell damage. However, no significant differences in either hepatic or cardiac levels of thiobarbituric acid reactive substances, a measure of lipid peroxidation, were found.
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PMID:Effects of copper deficiency on hepatic and cardiac antioxidant enzyme activities in lactose- and sucrose-fed rats. 253 51

Manganous (Mn) and copper zinc (CuZn) superoxide dismutase (SOD) concentrations and glutathione peroxidase (GSH-Px) and catalase (CAT) activities were measured in cultured bovine pulmonary endothelial cells with and without exposure to Escherichia coli endotoxin (10(-1) micrograms/ml) over intervals of 0.5-24 h. The activities of two mitochondrial marker enzymes, fumarase and cytochrome-c oxidase, were also measured. Endotoxin exposure caused a marked increase (9-fold) in endothelial cell Mn SOD content without significant effects on GSH-Px, CAT, fumarase, or cytochrome-c oxidase activities. Endotoxin induced a slight decrease in CuZn SOD content over 24 h. This is the first report of a selective effect of endotoxin on Mn SOD in pulmonary endothelial cells. The response appears to be independent of an increase in mitochondrial activity (no change was observed in cytochrome-c oxidase or fumarase activities). These findings support the notion that endotoxin increases generation of toxic oxygen metabolites within pulmonary endothelial cells. An endotoxin-induced increase in Mn SOD could contribute to the reported protective effect of endotoxin against oxygen toxicity in these cells.
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PMID:Endotoxin increases superoxide dismutase in cultured bovine pulmonary endothelial cells. 303 89

Histochemical alterations of acute and chronic doxorubicin (DOX) cardiotoxicity in the mouse were assessed by the localization of succinate dehydrogenase (SDH), coenzyme Q10 (CoQ), cytochrome oxidase (COX), creatine phosphokinase (CPK), lactate dehydrogenase (LDH), reduced glutathione (GSH), and intracellular calcium. Isolated myocytes intensely stained for calcium were found at 72 and 120 h under the acute protocol; altered staining patterns of SDH, CoQ, and COX, were evident at 120 h. Chronically, two patterns of intracellular calcium staining were evident: (1) intensely stained myocytes as found in the acute protocol; and (2) multiple discrete intracellular deposits suggestive of mitochondrial localization. Altered staining patterns of SDH, CoQ, COX, CPK, and LDH under the chronic protocol were only seen after abnormal staining was evident in trichrome stained sections. The presence of characteristic vacuolated myocardial cells in both acute and chronic protocols was confirmed by one micron epon-embedded toluidine blue stained sections and electron microscopy. These histochemical findings suggest that DOX alters the functional integrity of mitochondrial respiratory chain enzymes in the myocardial cell.
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PMID:Histochemical alterations of acute and chronic doxorubicin cardiotoxicity. 667 10

Mitochondria are an important source of reactive oxygen intermediates because they are the major consumers of molecular oxygen in cells. Respiration is associated with toxicity, which is related to the activation of oxygen to reactive intermediates. The purpose of the present study was to examine the role of reduced glutathione (GSH) in the maintenance of mitochondrial functions during oxidative stress induced through selective inhibition of the complex III segment of the electron transport chain. Hydrogen peroxide monitored by the fluorescence of dichlorofluorescein increased in a time- and dose-dependent manner on incubation of mitochondria with antimycin A (AA), an inhibitor of complex III. However, blockade of complex I or II with rotenone or thenoyltrifluoroacetone, respectively, did not result in accumulation of hydrogen peroxide. Depletion of mitochondrial GSH to 10-20% of control by preincubation with diethylmaleate (0.8 mM) or ethacrynic acid (250 microM) also increased dichlorofluorescein and malondialdehyde levels and resulted in an additional (2-3-fold) increase after AA. Similar results were obtained when mitochondrial GSH depletion was produced by treatment with buthionine L-sulfoximine before mirochondria isolation. The endogenous oxidative stress induced by AA was accompanied by a moderate loss of activity of ATPase complex (77% of control) and complex IV of respiration (75% of control), which was accentuated after depletion of mitochondrial GSH (51% and 45% of control, respectively). Similar results were observed in isolated hepatocytes in which depletion of mitochondrial GSH and AA led to peroxidation and mitochondrial dysfunction. In addition, with electrophoretic mobility shift assay of the transcription factor nuclear factor-kappa B (NF-kappa B), we detected its activation in response to AA (2-3-fold). Depletion of mitochondrial GSH in hepatocytes (20% of control) led to further enhancement of NF-kappa B activation (2-4-fold), which correlated with generation of hydrogen peroxide. Thus, our results suggest that GSH protects mitochondria against the endogenous oxidative stress produced at the ubiquinone site of the electron transport chain. Mitochondrial GSH depletion potentiates oxidant-induced loss of mitochondrial functions. Oxidant stress in mitochondria can promote extramitochondrial activation of NF-kappa B and therefore may affect nuclear gene expression.
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PMID:Role of oxidative stress generated from the mitochondrial electron transport chain and mitochondrial glutathione status in loss of mitochondrial function and activation of transcription factor nuclear factor-kappa B: studies with isolated mitochondria and rat hepatocytes. 747 12


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