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:1.6.5.3 (complex I)
8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously reported on the use of enzymatic analysis to impair fatty acid metabolism followed by reduced myocardial energy content, leading to severe heart failure in adriamycin (ADR)-treated rats. The aim of this study is to investigate whether impaired myocardial energy metabolism can also be detected by other methods; i.e. measuring mitochondrial complex I activity and myocardial 125I-15-(p-iodophenyl)-3-(R,S)- methylpentadecanoic acid (BMIPP) accumulation in ADR-treated rats. Eight-week-old male Sprague-Dawley rats received 6 intraperitoneal injections of ADR (total 15 mg/kg: group ADR) or saline (control group) over 2 weeks. Left ventricular (LV) ejection fraction was assessed using echocardiography at 3- and 6-weeks after ADR injection (3 weeks and 6 weeks, respectively). Myocardial fatty acid utilization was assessed at 3 weeks and 6 weeks. The myocardial counts of BMIPP were measured after intravenous BMIPP (370 kBq) injection, and 125I counts were measured to calculate the uptake ratio. The enzymatic activity of complex I was assessed by monitoring the oxidation of nicotinamide-adenine-dinucleotide-disodium-salt (NADH). In rats treated with ADR, significant decrease in LV ejection fraction was observed only at 6 weeks compared to control (72.5 vs. 84.5%, p < 0.01). LV ejection fraction at 3 weeks was identical between group ADR and control (81.8 vs. 84.4%). However, at 3 weeks, complex I activity was already reduced significantly in group ADR as compared to control group (p = 0.03), but the reduction in BMIPP accumulation was not (p = 0.15). Our data indicated that reduced complex I activity in a phenomenon occurred in early phase of ADR-induced cardiomyopathy, and it might play an important role in the progression of ADR-induced heart failure.
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PMID:Mitochondrials complex I activity is reduced in latent adriamycin-induced cardiomyopathy of rat. 1287 Jun 75

Treatment of SH-SY5Y human neuroblastoma cells with copper sulphate (50-300microM) in complete medium for 24h caused an increase in the level of the metal both in whole cells and in isolated mitoplasts. Toxic effects of copper resulted in the impairment of the capability of mitochondrial dehydrogenases to reduce a tetrazolium salt, and, to a lesser extent, in the loss of the integrity of the plasma membrane. The mechanism of toxicity involved the production of reactive oxygen species, amplified by the presence of ascorbate. Decreases in the levels of several mitochondrial proteins (subunits of complex I, complex V, and of the pyruvate dehydrogenase complex) were observed. These findings demonstrate that mitochondria are an early and susceptible target of copper-mediated oxidative stress in neuronal cells and support the hypothesis that mitochondrial damage triggers the neurodegenerative processes associated with copper overload in Wilson's disease.
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PMID:Copper-dependent toxicity in SH-SY5Y neuroblastoma cells involves mitochondrial damage. 1562 36

Tirandamycin inhibits respiration and phosphorylation in rat liver mitochondria. An investigation of individual reaction sequences occurring within the respiratory chain showed that the antibiotic stimulates reduced nicotinamide adenine dinucleotide (NADH)- and succinate-linked coenzyme Q reductase. NADH-linked reduction of tetrazolium salts remains unaffected by tirandamycin. Succinotetrazolium salt reductase is inhibited significantly. Reduction of cytochrome c by succinate is blocked by the antibiotic; NADH-cytochrome c reductase is inhibited but not completely blocked. Cytochrome c oxidase remains unaffected. Mitochondrial difference spectra prepared in the presence of tirandamycin indicate that the reduction of cytochrome b is not impaired but no reduction of cytochromes c or a is apparent. These results indicate that tirandamycin interferes with the respiratory chain at a point beyond the cytochrome b and prior to the cytochrome c reduction site. Tirandamycin acts also as a potent inhibitor of ribonucleic acid polymerase as discussed in the foregoing paper.
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PMID:Tirandamycin: inhibition of oxidative phosphorylation in rat liver mitochondria. 1655 5

Ferricyanide is actively reduced by intact maize (Zea mays L., var XL 342) roots. This reduction is salt and temperature dependent, is stimulated by fusicoccin, and is accompanied by decrease of external pH. In anaerobic conditions, ferricyanide partially restores fusicoccin-induced proton extrusion. A salt-, temperature-, and pH-dependent cyanide-insensitive NADH-ferricyanide oxidoreductase activity can be demonstrated in microsomes isolated from the same plant tissue. This evidence supports the hypothesis, as proposed by Craig and Crane (1982 Plant Physiol 67: S-558, S-835), that the ferricyanide reduction is carried out by a transmembrane NADH dehydrogenase.
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PMID:A transplasmamembrane electron transport system in maize roots. 1666 72

It has been documented that dietary copper (Cu) deficiency impairs mitochondrial respiratory function, which is catalyzed by 5 membrane-bound multiple protein complexes. However, there are few reports on the simultaneous analysis of Cu effect on the subunit protein expression on all 5 protein complexes. The present study was undertaken to determine the effect of Cu deficiency on each mitochondrial respiratory complex's protein expression in rat heart tissue with western-blot analysis. Male Sprague-Dawley rats were fed diets that were either Cu adequate (6.0 microg Cu/g diet, n = 5) or Cu deficient (0.3 microg Cu/g diet, n = 5) for 5 wk. The monoclonal antibody-based western-blot analysis suggested that the protein levels of 39-kDa and 30-kDa subunits in complex I; 70-kDa and 30-kDa subunits in complex II; core I and core II subunits in complex III; and alpha and beta subunits of F1 complex in complex V in both high-salt buffer (HSB) and low-salt buffer (LSB) protein fractions from heart tissue of Cu-deficient rats did not differ from those of Cu-adequate rats. However, the protein level of cytochrome c oxidase (CCO) subunit (COX) I, COX Vb, and COX VIb subunits in complex IV (CCO) in both HSB and LSB protein fractions from heart tissue of Cu-deficient rats was lower than those of Cu-adequate rats. Collectively, these data demonstrate that Cu deficiency decreases each tested subunit protein expression of complex IV but not those of complex I, II, III, and V in mitochondrial respiratory complexes.
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PMID:Copper deficiency decreases complex IV but not complex I, II, III, or V in the mitochondrial respiratory chain in rat heart. 1718 94

NADH:ubiquinone oxidoreductase (complex I ) of the mitochondrial respiratory chain catalyzes the transfer of electrons from NADH to ubiquinone coupled to proton translocation across the membrane. The cDNA sequence of Dunaliella salina mitochondrial NADH: ubiquinone oxidoreductase 19-kD subunit contains a 682-bp ORF encoding a protein with an apparent molecular mass of 19 kD. The sequence has been submitted to the GenBank database under Accession No. EF566890 (cDNA sequences) and EF566891 (genomic sequence). The deduced amino-acid sequence is 74% identical to Chlamydomonas reinhardtii mitochondrial NADH:ubiquinone oxidoreductase 18-kD subunit. The 19-kD subunit mRNA expression was observed in oxygen deficiency, salt treatment, and rotenone treatment with lower levels. It demonstrate that the 19-kD subunit of Complex I from Dunaliella salina is regulated by these stresses.
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PMID:Cloning and sequence analysis of the gene encoding 19-kD subunit of Complex I from Dunaliella salina. 1753 Apr 40

It has been well appreciated that aldosterone (Aldo) plays a direct profibrotic role in the kidney but the underlying mechanism is unclear. We examined the role of Aldo in epithelial-mesenchymal transition (EMT) both in vitro and in vivo. Exposure of human renal proximal tubular cells to Aldo for 48 h dose dependently induced EMT as evidenced by conversion to the spindle-like morphology, loss of E-cadherin, and de novo expression of alpha-smooth muscle actin (SMA); the effect was noticeable at 50 nM and maximal at 100 nM. The EMT was completely blocked by the selective mineralocorticoid receptor (MR) antagonist eplerenone. Aldo time dependently increased intracellular reactive oxygen species (ROS) production that was detectable at 15 min and peaked (2.3-fold) at 60 min, as assessed by 2',7'-dichlorofluorescin diacetate fluorescence. Aldo-induced oxidative stress and EMT were both abolished by the mitochondrial respiratory chain complex I inhibitor rotenone, but not the NADPH oxidase inhibitor apocynin. Aldo induced phosphorylation of ERK1/2 that was completely blocked by rotenone. Male 129-C57/BL6 mice were treated with deoxycorticosterone acetate (DOCA) salt (subcutaneous implantation of 50 mg of DOCA pellet plus 1% NaCl as drinking fluid) for 3 wk and animals were treated with vehicle or rotenone (600 ppm in diet) for the last week. DOCA salt induced a 2.5-fold increase in alpha-SMA and a 30% reduction of E-cadherin, as assessed by real-time RT-PCR, that were both restricted to renal epithelial cells, as determined by immunohistochemistry. In contrast, DOCA salt-induced changes in alpha-SMA and E-cadherin were completely blocked by treatment with rotenone. These observations suggest that Aldo induces EMT via MR-mediated, mitochondrial-originated, ROS-dependent ERK1/2 activation in renal tubular epithelial cells.
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PMID:Aldosterone induces epithelial-mesenchymal transition via ROS of mitochondrial origin. 1759 22

Vascular superoxide anion (O(2)(*-)) levels are increased in DOCA-salt hypertensive rats. We hypothesized that the endothelin (ET)-1-induced generation of ROS in the aorta and resistance arteries of DOCA-salt rats originates partly from xanthine oxidase (XO) and mitochondria. Accordingly, we blocked XO and the mitochondrial oxidative phosphorylation chain to investigate their contribution to ROS production in mesenteric resistance arteries and the aorta from DOCA-salt rats. Systolic blood pressure rose in DOCA-salt rats and was reduced after 3 wk by apocynin [NAD(P)H oxidase inhibitor and/or radical scavenger], allopurinol (XO inhibitor), bosentan (ET(A/B) receptor antagonist), BMS-182874 (BMS; ET(A) receptor antagonist), and hydralazine. Plasma uric acid levels in DOCA-salt rats were similar to control unilaterally nephrectomized (UniNx) rats, reduced with allopurinol and bosentan, and increased with BMS. Levels of thiobarbituric acid-reacting substances were increased in DOCA-salt rats versus UniNx rats, and BMS, bosentan, and hydralazine prevented their increase. Dihydroethidium staining showed reduced O(2)(*-) production in mesenteric arteries and the aorta from BMS- and bosentan-treated DOCA-salt rats compared with untreated DOCA-salt rats. Increased O(2)(*-) derived from XO was reduced or prevented by all treatments in mesenteric arteries, whereas bosentan and BMS had no effect on aortas from DOCA-salt rats. O(2)(*-) generation decreased with in situ treatment by tenoyltrifluoroacetone and CCCP, inhibitors of mitochondrial electron transport complexes II and IV, respectively, whereas rotenone (mitochondrial complex I inhibitor) had no effect. Our findings demonstrate the involvement of ET(A) receptor-modulated O(2)(*-) derived from XO and from mitochondrial oxidative enzymes in arteries from DOCA-salt rats.
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PMID:Xanthine oxidase and mitochondria contribute to vascular superoxide anion generation in DOCA-salt hypertensive rats. 1848 45

Cyclic electron transport and NADH and/or NADPH (NAD(P)H)-oxidizing activities were investigated in Synechocystis sp. PCC6803 grown under various stressed conditions and in ndhB-less (M55) and ycf33-deletion mutants. Activity staining and inhibitor data suggested that the ferredoxin-quinone reductase (FQR) route is the main pathway in ycf33-deletion and high-light (300 microE m(-2) s(-1))-grown cells as well as in M55 cells. The FQR route was highly sensitive to HgCl(2), but not to diphenyleneiodonium (DPI). On the other hand, cells grown under low CO(2) (0.03%) or normal (100 microE m(-2) s(-1), 3% CO(2)) conditions were found perhaps to use the complex I-type NAD(P)H dehydrogenase route, which was found to be highly sensitive to DPI but not to HgCl(2). In high-salt (0.55 M NaCl)-grown cells, the amount of ferredoxin-NADP(+) oxidoreductase (FNR) increased, and the main cyclic electron flow was perhaps the FNR route. Both DPI and HgCl(2) were strong inhibitors of the FNR route.
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PMID:The expression pattern of NAD(P)H oxidases and the cyclic electron transport pathway around photosystem I of Synechocystis sp. PCC6803 depend on growth conditions. 1906 Apr 5

Anabaena sp. PCC7120 contains a gene, mrpA (all1838), which forms part of a seven gene-cluster (all1843-all1837) with significant sequence similarity to bacterial operons that putatively code for a multicomponent cation/proton antiporter involved in alkaline pH adaptation and salt resistance. We previously showed that growth and photosynthesis were inhibited in a strain mutated in mrpA, denoted as PHB11, particularly at alkaline pH. Here, we show that respiration was also impaired in the mutant independently of the external pH. In addition, at high pH, less ATP and vegetative cell ferredoxin were present in PHB11, which also showed lower levels of ferredoxin-NADP(+) oxidoreductase (FNR). Ferredoxin and FNR are involved in the generation of reductant NADPH in cyanobacteria. These results suggest an energetic role of mrpA (and perhaps of the whole mrp-gene cluster) in Anabaena sp. PCC 7120 that is further supported by the significant similarity of putative Anabaena Mrp proteins to membrane subunits of complex I.
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PMID:mrpA (all1838), a gene involved in alkali and Na(+) sensitivity, may also have a role in energy metabolism in the cyanobacterium Anabaena sp. strain PCC 7120. 1941 Mar 33


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