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)

Changes in the content of dipicolinic acid and mineral elements were studied in the process of Bacillus thuringiensis spore germination. The spores released up to 28% of dipicolinic acid and 18% of calcium at the activation stage, and 93 and 91%, respectively, at the initiation stage. At the same time, the content of Mg, Mn, Zn and P decreased while K, Na and Fe accumulated in the spores. The activities of total and serine proteases, alkaline phosphatase, NADH dehydrogenase and aldolase increased in the extract of initiated spores. The content of glutamate decreased in the free amino acid pool as early as by the 30th second of the initiation stage.
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PMID:[Amino acid and mineral element content and the activity of various enzymes in germinating spores of Bacillus thuringiensis]. 389 44

We have used genomic DNA from human or mouse cells as a calcium phosphate precipitate to transfect three different respiration-deficient Chinese hamster mutant cell lines with defects in complex I of the electron transport chain. Transformants were selected in DMEM containing galactose, a medium in which respiration-deficient cells do not grow. Evidence for the DNA-mediated transformation of these respiration-deficient cells with a putative complex I gene includes: the clones are respiration-positive and respire at rates comparable to those of wild-type human, hamster, or mouse cells; the clones have rotenone-sensitive NADH oxidase activities, indicating a functional complex I of the electron transport chain; and the clones appear to be true transformants, as demonstrated by hybridization and Southern blot analyses. These experiments provide the basis for the isolation and subsequent characterization of several of the genes involved with complex I of the mammalian electron transport chain.
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PMID:DNA-mediated transfer of complex I genes into three different respiration-deficient Chinese hamster mutant cell lines with defects in complex I of electron transport chain. 392 93

1. Reactions between triphosphoinositide and the basic experimental allergic encephalitogenic (EAE) protein were examined in aqueous solution and in a biphasic solvent system (chloroform-methanol-water, 8:4:3, by vol.). 2. In the absence of salt an insoluble complex (I) is formed containing triphosphoinositide and EAE protein in proportions that represent complete neutralization of lipid and protein at the pH concerned. 3. In the presence of a low concentration (0.05m) of sodium chloride an insoluble positively charged complex (II) forms. It contains triphosphoinositide and EAE protein in a lower concentration ratio than complex I. This complex, which has a constant composition between pH7.5 and pH10, can take up additional micellar triphosphoinositide producing complex I, which can then be solubilized by excess of triphosphoinositide. 4. The complexes are dissociated by more concentrated sodium chloride solutions and low concentrations of calcium chloride, suggesting that they are largely stabilized by electrostatic bonds. The protein recovered after dissociation is immunologically active and has the same electrophoretic mobility as the original. 5. Water-insoluble ternary complexes containing triphosphoinositide, EAE protein and large amounts of phosphatidylcholine can be prepared. From these, chloroform-methanol (2:1, v/v) extracts only phosphatidylcholine. 6. An insoluble ternary complex of Ca(2+) ion, EAE protein and triphosphoinositide can be prepared by adding calcium chloride to a complex I preparation solubilized by excess of triphosphoinositide. 7. EAE protein will also form complexes with other acidic phospholipids, e.g. phosphatidic acid, phosphatidylserine and phosphatidylinositol, but not with phosphatidylcholine or phosphatidylethanolamine. The phosphatidylinositol and phosphatidylserine complexes are chloroform soluble, i.e. proteolipids. 8. The possibility that complexes between EAE protein and acidic phospholipids occur in vivo is discussed. Triphosphoinositide and EAE protein occur in ox brain myelin in approximately the same concentration ratios as they do in complex II, formed at physiological salt concentration and pH.
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PMID:Complex-formation between triphosphoinositide and experimental allergic encephalitogenic protein. 430 66

A purified, active succinate-ubiquinone reductase was prepared from succinate-cytochrome c reductase without damage to ubiquinol-cytochrome c reductase by 1.1% Triton X-100 solubilization at pH 8.0, and calcium phosphate column chromatography in 50 mM Tris-succinate buffer, pH 8.0, containing 30 mM potassium phosphate. Succinate-ubiquinone reductase thus obtained contains ubiquinone and catalyzes thenoyltrifluoroacetone-sensitive oxidation of succinate by 2,6-dichlorophenolindophenol in the absence of exogenous mediator. Addition of ubiquinone enhanced the activity about 50%. Analytical sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that the enzyme contains four polypeptides. The high molecular weight polypeptide contaminants usually observed in the Complex II preparation obtained by the reported method were absent. The active succinate-ubiquinone reductase can reconstitute with the cytochrome b-c1III complex, or Complex III to form succinate-cytochrome c reductase in the absence of exogenous ubiquinone or with the resolved ubiquinol-cytochrome c reductase in the presence of ubiquinone and phospholipids. Under the proper conditions, all the original succinate-cytochrome c reductase was obtained, indicating that the resolution caused no damage to the protein, despite the removal of phospholipids and ubiquinone from the ubiquinol-cytochrome c reductase region.
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PMID:Quantitative resolution of succinate-cytochrome c reductase into succinate-ubiquinone and ubiquinol-cytochrome c reductases. 627 4

Ca2+-dependent K+ transport and plasma membrane NADH dehydrogenase activities have been studied in several 'high-K+' (human, rabbit and guinea pig) and 'low-K+' (dog, cat and sheep) erythrocytes. All the species except sheep showed Ca2+-dependent K+ transport. NADH-ferricyanide reductase was detected in all the species and showed positive correlation with the flavin contents of the membranes. NADH-cytochrome c reductase was very low or absent in dog, sheep and guinea pig membranes. No correlation was found between NADH dehydrogenase and Ca2+-dependent K+ channel activities in the species studied. Nor were any of the above activities correlated with (Na+ + K+)-ATPase activity.
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PMID:Plasma membrane nadh dehydrogenase and Ca2+-dependent potassium transport in erythrocytes of several animal species. 640 2

The external NADH dehydrogenase has been purified from Arum maculatum (cuckoo-pint) mitochondria by phosphate washing, extraction with deoxycholate, ion-exchange and gel-filtration chromatography. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis shows, when the gel is silver-stained, that the purified enzyme contains two major bands of Mr 78 000 and 65 000 and a minor one of Mr about 76 000. It is not possible at present to determine which of these, or which combination, constitutes the dehydrogenase. The enzyme contains non-covalently bound FAD and a small amount of FMN. Since the conditions of purification lead to considerable loss of flavin and possibly iron-sulphur centres, it is not possible to decide with certainty whether the enzyme is a flavo- or ferroflavo-protein. The enzyme has been distinguished from the other NADH dehydrogenases on the basis of its substrate specificity, its capability of reducing electron acceptors such as ubiquinone-1 and 2,6-dichlorophenol-indophenol and its sensitivity towards Ca2+, EGTA and dicoumarol.
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PMID:Partial purification and properties of the external NADH dehydrogenase from cuckoo-pint (Arum maculatum) mitochondria. 650 55

TMB-8 inhibited respiration of rat thymocytes and rat liver mitochondria, probably by inhibition of NADH dehydrogenase. TMB-8 markedly decreased both the cellular ATP concentration and the mitochondrial membrane potential in situ in thymocytes. These effects occurred at, or well below, the concentrations used in other systems to investigate the role of intracellular calcium pools in signalling events. We conclude that caution should be exercised in the interpretation of the effects of TMB-8.
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PMID:The intracellular calcium antagonist TMB-8 [8-(NN-diethylamino)octyl-3,4,5-trimethoxybenzoate] inhibits mitochondrial ATP production in rat thymocytes. 652 71

The ability of mitochondria to take up and retain Ca2+, and thereby to effect the free intracellular concentration of this ion, is well established. More recently, it has been reported (Lehninger, A. L., Vercesi, A., and Bababunmi, E. A. (1978) Proc. Natl. Acad. Sci. U. S. A. 75, 1690-1696) that the redox state of pyridine nucleotides modulates mitochondrial Ca2+ balance, since the oxidation of mitochondrial NAD(P)H is associated with the release of Ca2+ from these organelles. The latter may be achieved by a variety of treatments including the incubation of Ca2+-loaded liver mitochondria with hydroperoxides, the metabolism of which by the glutathione peroxidase-glutathione reductase system results in NADPH consumption. The metabolism of menadione (2-methyl-1,4-naphthoquinone) by Ca2+-loaded rat liver mitochondria results in rapid oxidation and loss of pyridine nucleotides and a decrease in ATP level. It is also associated with Ca2+ release and an impaired ability of the mitochondria to take up and retain Ca2+. The effects of menadione on mitochondrial Ca2+ balance are more rapid and pronounced than those of t-butylhydroperoxide, and in contrast to those observed with the hydroperoxide, they are not abolished by pretreatment with a glutathione-depleting agent. The effects of menadione on Ca2+ homeostasis are probably initiated by NAD(P)H oxidation linked to the reduction of menadione by both NADH-ubiquinone oxidoreductase and NAD(P)H:(quinone-acceptor) oxidoreductase.
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PMID:The metabolism of menadione impairs the ability of rat liver mitochondria to take up and retain calcium. 711 97

Differences among cystic fibrosis (CF) genotypes (CF, obligate carriers for CF [HZ], and controls) in mitochondrial calcium pool size, oxygen (O2) consumption, and rotenone inhibition of O2 consumption led to examination of mitochondrial NADH dehydrogenase (NADH: [acceptor] oxidoreductase, E.C. 1.6.99.3). pH optima of mitochondrial NADH dehydrogenase were different in enzyme derived from whole cell homogenates of cultured skin fibroblasts of subjects with CF, HZ, and controls. We describe here apparent binding of substrate to the enzyme (Km [NADH]) in cell fractions. Km (NADH) for CF ranged from 10.9 to 16.1 micro M (no. = 7); for HZ from 20.9 to 26.3 microM (no. = 5). With three exceptions, Km for controls (no. = 12) ranged from 31.8 to 42.8 microM. Km of the three exceptional controls were 21.5, 23.7, and 22.4 microM (the latter two are identical twins). pH optima of enzyme from these three strains were no different from that of known HZ. The correlation between two kinetic parameters of an enzyme and the three CF genotypes suggests an association between the CF gene and mitochondrial NADH dehydrogenase.
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PMID:Mitochondrial NADH dehydrogenase in cystic fibrosis: enzyme kinetics in cultured fibroblasts. 718 Aug 43

1. The convulsant barbiturate 5-(2-cyclohexylidene-ethyl)-5-ethyl barbituric acid (CHEB) depolarizes dorsal root ganglion (DRG) neurons. We have applied microfluorimetric and whole-cell patch clamp techniques to investigate the mechanisms underlying this response in freshly dissociated mouse DRG cells. 2. Application of CHEB (2-200 microM) raised cytosolic calcium concentration ([Ca2+]i) rapidly and reversibly in 55% of eighty-three neurons tested. This population did not correlate with other classifications of sensory neurons based on either cell size or the expression of membrane currents. 3. The response was dependent on external calcium and was reduced by 81 +/- 22% by Ruthenium Red. A rise in [Ca2+]i was still seen with the membrane potential clamped at -70 mV, excluding membrane depolarization and activation of voltage-dependent Ca2+ channels as the principal mechanism for the response. 4. The rise in [Ca2+]i was associated with an increase in membrane conductance and a current, ICHEB, which was inward at -70 mV. Both the rise in [Ca2+]i and the current showed 'run-down' under whole-cell recording conditions. When K+ conductances were blocked, the reversal potential of ICHEB was close to 0 mV. This was independent of the Cl- reversal potential, suggesting that ICHEB is carried as a non-specific cation current. 5. In contrast to the change in [Ca2+]i, ICHEB was not dependent on external Ca2+ and the current was still seen when [Ca2+]i as strongly buffered by the pipette filling solution. These data suggest that CHEB opens a non-selective cation channel permeant to Ca2+, raising [Ca2+]i and further depolarizing the cell membrane potential. The exact nature of this conductance remains unknown. These actions could readily account for the convulsant actions of the drug, depolarizing neurons and increasing transmitter release. 6. It was also noted that CHEB increases autofluorescence derived from mitochondrial NAD(P)H. Further examination of this phenomenon using the dye rhodamine 123 to follow changes in mitochondrial potential (psi m) suggested that CHEB is a potent inhibitor of mitochondrial respiration, probably acting at complex I. These effects appeared to be quite distinct from the action of CHEB at the level of the plasma membrane.
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PMID:Electrophysiological and metabolic effects of a convulsant barbiturate on dissociated mouse primary sensory neurons. 754 7


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