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)

The effect of water extracts of cinnamon and clove on rat mitochondrial F(0)F1ATPase was investigated. Both spices stimulated ATP hydrolysis. Gas chromatography analysis of the water extracts, confirmed the presence of eugenol and cinnamaldehyde as major components in clove and cinnamon, respectively. Both components (1) stimulated ATPase significantly at concentrations equal or greater then 0.3 mM; (2) reduced mitochondrial membrane potential: a 50% decrease in Deltapsi was obtained at 7.56 and 11.6 micromoles/mg protein for eugenol and cinnmaldehyde, respectively; (3) inhibited NADH oxidase or complex I of the respiratory chain with a 50% inhibition at 15 and 20 micromoles/mg protein for eugenol and cinnamaldehyde respectively; (4) had no effect on succinate dehydrogenase activity. The study proposes the mitochondria as a target for the action of the spices resulting in derangement of mitochondrial functions, particularly at proton transferring sites.
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PMID:In vitro effect of eugenol and cinnamaldehyde on membrane potential and respiratory chain complexes in isolated rat liver mitochondria. 1206 15

To study low-temperature signaling in plants, we previously screened for cold stress response mutants using bioluminescent Arabidopsis plants that express the firefly luciferase reporter gene driven by the stress-responsive RD29A promoter. Here, we report on the characterization and cloning of one mutant, frostbite1 (fro1), which shows reduced luminescence induction by cold. fro1 plants display reduced cold induction of stress-responsive genes such as RD29A, KIN1, COR15A, and COR47. fro1 leaves have a reduced capacity for cold acclimation, appear water-soaked, leak electrolytes, and accumulate reactive oxygen species constitutively. FRO1 was isolated through positional cloning and found to encode a protein with high similarity to the 18-kD Fe-S subunit of complex I (NADH dehydrogenase, EC 1.6.5.3) in the mitochondrial electron transfer chain. Confocal imaging shows that the FRO1:green fluorescent protein fusion protein is localized in mitochondria. These results suggest that cold induction of nuclear gene expression is modulated by mitochondrial function.
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PMID:A mitochondrial complex I defect impairs cold-regulated nuclear gene expression. 1208 24

Chlororespiration has been defined as a respiratory electron transport chain (ETC) in interaction with the photosynthetic ETC in thylakoid membranes of chloroplasts. The existence of chlororespiration has been disputed during the last decade, with the initial evidence mainly obtained with intact algal cells being possibly explained by redox interactions between chloroplasts and mitochondria. The discovery in higher-plant chloroplasts of a plastid-encoded NAD(P)H-dehydrogenase (Ndh) complex, homologous to the bacterial complex I, and of a nuclear-encoded plastid terminal oxidase (PTOX), homologous to the plant mitochondrial alternative oxidase, brought molecular support to the concept of chlororespiration. The functionality of these proteins in non-photochemical reduction and oxidation of plastoquinones (PQs), respectively, has recently been demonstrated. In thylakoids of mature chloroplasts, chlororespiration appears to be a relatively minor pathway compared to linear photosynthetic electron flow from H2O to NADP+. However, chlororespiration might play a role in the regulation of photosynthesis by modulating the activity of cyclic electron flow around photosystem I (PS I). In non-photosynthetic plastids, chlororespiratory electron carriers are more abundant and may play a significant bioenergetic role.
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PMID:Chlororespiration. 1222 39

There is a known connection between selenium supplementation and chemo-protective anti-cancer activity. This biological phenomenon may be due to the ability of selenium to instigate cellular apoptosis. However, the mechanism by which selenium promotes cellular apoptosis is still obscure. The present study shows that sodium selenite, a common dietary form of selenium, promotes the mitochondrial permeability transition (MPT) in isolated rat liver mitochondria both in vitro and following in vivo supplementation. A low selenium concentration (0.1-10 microM) strongly induced cyclosporin A-sensitive mitochondrial swelling. Selenium also promoted both calcium release from the matrix of isolated mitochondria and uncoupled respiration. The MPT-inducing effect of selenium provoked the release of cytochrome c, a pro-apoptotic factor, into the incubation medium. Selenium did not increase intra-mitochondrial peroxide production, but did consume endogenous mitochondrial glutathione. Moreover, the effect of MPT induction was greatly potentiated in the presence of thiol-bearing antioxidants, e.g. N -acetylcysteine and lipoamide. During MPT progression, selenium induced NADH oxidation via electron acceptance from complex I. Supplementation for 20 days with 16 p.p.m. selenium in the drinking water of rats increased the propensity of mitochondria to undergo the MPT. More marked mitochondrial swelling in response to calcium and lower calcium-uptake capacity were observed, in the absence of liver damage or the intensive oxidation of reduced glutathione. Therefore selenite facilitates MPT pore opening via its thiol- and NADH/complex I-dependent reduction, and thereby may provide chemo-protection by potentiation of the capacity of the mitochondria to regulate programmed cell death. Data from the present study suggest that selenium can regulate important mitochondrial functions both in vivo and in vitro.
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PMID:Selenite sensitizes mitochondrial permeability transition pore opening in vitro and in vivo: a possible mechanism for chemo-protection. 1242 4

Germanium complexes (IV) with succinic (H2Suc), oxyethyliminodiacetic (H2Oeida) and iminodisuccinic (H4Ids) acids as well as homo- and heteroligand germanium complexes (IV)--products of interaction of triammonium salt of oxyethylidendiphosphonic acid ((NH4)3HL) and oxyacids: tartaric (H4Tart), citric (H4Citr), trioxyglutaric (H4Toglut) acids have been synthesized. Composition of the obtained complexes: [Ge(OH)2(NaSuc)2].2H2O (I); [Ge(OH) (Oeida).H2O].H2O (II); [Ge(OH)2(NaHIds)2] (III); [Ge(OH)2(NH4)3HL) (H2Tart)] (IV); [Ge(OH)2(NH4)3HL) (H2Citr)] (V); [Ge(OH)2(NH4)3HL) (H2Toglut)] (VI); [Ge(OH)2((NH4)2HL)2] (VII); [Ge (OH)2((NH4)2HL)2] (VII); [Ge(OH)2 (H2O)2(NH4) HL] (VIII) has been determined. The capability of the synthesized compounds has been studied to affect synthesis and activity of the following enzymes: collagenase, alpha-N-acetylgalactosaminidase (alpha-GalNAc-ase) and alpha-galactosidase (alpha-Gal-ase). It has been established that the complexes II-VIII activate biosynthesis of alpha-Gal-ase and alpha-GalNAc-ase, while germanium dioxide (IX) and complex I possess considerable inhibiting effect on synthesis of the above enzymes. It has been also established that all the compounds except for IV increased the activity of both alpha-Gal-ase and alpha-GalNAc-ase. All the considered complexes demonstrated similar reaction with respect to collagenase: they inhibited both synthesis and activity.
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PMID:[Effect of coordinational germanium compounds on enzyme synthesis and activity]. 1243 65

Survival, electron transport system (ETS) activity and the activity of NADH and succinate dehydrogenase of Escherichia coli ML30 were studied under starvation stress at different temperatures in a filtered-autoclaved lake water microcosm. ETS activity in E. coli declined rapidly at 30 degrees C but more slowly at 4 degrees and 15 degrees C over a 20 d starvation period. The decrease in ETS activity in E. coli only started after 6 d of incubation at 4 degrees C and 15 degrees C. Viability of E. coli, as determined by plate counts, declined faster at 37 degrees C than at the other temperatures and remained highest at 4 degrees C in filtered-autoclaved lake water. There was also a significant cell size reduction at 37 degrees C in filtered-autoclaved lake water but not at 4 degrees C. ETS activity after up to 16 d of starvation increased after the addition of nutrient broth to the filtered-autoclaved lake water at 15 degrees C and 30 degrees C suggesting that cells were still able to respond to nutrients, even after prolonged starvation. The response to the addition of nutrient broth, however, declined with the length of the starvation period. The activity of both succinate and NADH dehydrogenase declined over a 13 d starvation period. The loss of activity was fastest at 37 degrees C compared to lower incubation temperatures but even at 4 degrees C, a significant proportion of the activity was lost over the 13 d period.
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PMID:Relationship between respiratory enzymes and survival of Escherichia coli under starvation stress in lake water. 1245 93

Oxidative stress to vascular endothelium plays an important role in cold ischemia-reperfusion (CIR) injury. We compared mitochondrial and plasma membrane integrity in human endothelial cells after 20-min exposure to 500 microM H2O or 8-hr cold ischemia and simulated reperfusion. In both groups, plasma membrane integrity was maintained but respiration was significantly decreased, as measured by high-resolution respirometry. Uncoupling was more pronounced after H2O exposure compared with CIR. After H2O exposure, complex I respiration was significantly reduced, whereas CIR resulted additionally in a significant inhibition of complex II and IV respiration. Our results point to a partial overlap of the patterns of mitochondrial defects after H2O-mediated and CIR injury. In this respect, H2O exposure proved to be a useful model to study the mechanisms of CIR injury to human endothelial cells, whereas the full pattern of CIR injury could not be induced by a pulse of hydrogen peroxide exposure.
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PMID:H2O2-mediated oxidative stress versus cold ischemia-reperfusion: mitochondrial respiratory defects in cultured human endothelial cells. 1249 3

Three new ligands, N-(8-quinolyl)pyridine-2-carboxamide (HL1), N-(8-quinolyl)glycine-N'-Boc-carboxamide (HL2), N-(8-quinolyl)-L-alanine-N'-Boc-carboxamide (HL3), and their Cu(II) complexes have been synthesized. Crystallographic data reveal that complex I, [Cu(L1)(Ac)(H2O)], is penta-coordinated with a square-pyramidal geometry while complexes V [Cu(L2')(H2O)] and VI [Cu(L3')(H2O)] are tetra-coordinated to give square planar geometry. In vitro tests showed that the Cu(II) complexes with L1 (I-IV) exhibited cytotoxicity at a concentration of 10(-8) M against murine leukemia P-388 and human leukemia HL-60 cell lines, which is more potent than cisplatin. However, ligands HL2 and HL3 and their corresponding copper complexes demonstrated very weak in vitro activities towards the cell lines examined. ESMS data shows that complex I binds rapidly with 5'-GMP to form 1:1 and 2:2 adduct.
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PMID:Novel Cu(II)-quinoline carboxamide complexes: structural characterization, cytotoxicity and reactivity towards 5'-GMP. 1268 Jul 13

We previously showed that hydrogen peroxide (H2O2) contributes to flow-induced dilation in human coronary resistance arteries (HCRAs); however, the source of this H2O2 is not known. We hypothesized that the H2O2 is derived from superoxide (O2*-) generated by mitochondrial respiration. HCRAs were dissected from right atrial appendages obtained from patients during cardiac surgery and cannulated with micropipettes. H2O2-derived radicals and O2*- were detected by electron spin resonance (ESR) using BMPO as the spin trap and by histofluorescence using hydroethidine (HE, 5 micromol/L) and dichlorodihydrofluorescein (DCFH, 5 micromol/L). Diameter changes to increases in pressure gradients (20 and 100 cm H2O) were examined in the absence and the presence of rotenone (1 micromol/L), myxothiazol (100 nmol/L), cyanide (1 micromol/L), mitochondrial complex I, III, and IV inhibitors, respectively, and apocynin (3 mmol/L), a NADPH oxidase inhibitor. At a pressure gradient of 100 cm H2O, ubisemiquinone and hydroxyl radicals were detected from effluents of vessels. Including superoxide dismutase and catalase in the perfusate reduced the ESR signals. Relative ethidium and DCFH fluorescence intensities in HCRAs exposed to flow were enhanced (1.45+/-0.15 and 1.57+/-0.12, respectively compared with no-flow) and were inhibited by rotenone (0.87+/-0.17 and 0.95+/-0.07). Videomicroscopic studies showed that rotenone and myxothiazol blocked flow-induced dilation (% max. dilation at 100 cm H2O: rotenone, 74+/-3% versus 3+/-13%; myxothiazol, 67+/-3% versus 28+/-4%; P<0.05). Neither cyanide nor apocynin altered flow-induced dilation. These results suggest that shear stress induced H2O2 formation, and flow-induced dilation is derived from O2*- originating from mitochondrial respiration.
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PMID:Mitochondrial sources of H2O2 generation play a key role in flow-mediated dilation in human coronary resistance arteries. 1291 51

Mitochondrial proton-translocating NADH:ubiquinone oxidoreductase (complex I) couples the transfer of two electrons from NADH to ubiquinone to the translocation of four protons across the mitochondrial inner membrane. Subunit PSST is the most likely carrier of iron-sulfur cluster N2, which has been proposed to play a crucial role in ubiquinone reduction and proton pumping. To explore the function of this subunit we have generated site-directed mutants of all eight highly conserved acidic residues in the Yarrowia lipolytica homologue, the NUKM protein. Mutants D99N and D115N had only 5 and 8% of the wild type catalytic activity, respectively. In both cases complex I was stably assembled but electron paramagnetic resonance spectra of the purified enzyme showed a reduced N2 signal (about 50%). In terms of complex I catalytic activity, almost identical results were obtained when the aspartates were individually changed to glutamates or to glycines. Mutations of other conserved acidic residues had less dramatic effects on catalytic activity and did not prevent assembly of iron-sulfur cluster N2. This excludes all conserved acidic residues in the PSST subunit as fourth ligands of this redox center. The results are discussed in the light of the structural similarities to the homologous small subunit of water-soluble [NiFe] hydrogenases.
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PMID:Two aspartic acid residues in the PSST-homologous NUKM subunit of complex I from Yarrowia lipolytica are essential for catalytic activity. 1293 Aug 34


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