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 ethanol-extracted respiratory chain-linked NADH dehydrogenase of Acholeplasma laidlawii has been purified 25-35-fold. This purification involved delipidation of the ethanol-extracted minute non-sedimentable membrane fragments by detergent treatment and gel filtration on Bio-Gel P-200. Sodium deoxycholate-sucrose density gradient centrifugation was followed by dialysis of the active NADH dehydrogenase fractions which caused flocculation of 60% of the membrane proteins while the NADH dehydrogenase remained suspended. Poylacrylamide gel electrophoresis of the purified NADH dehydrogenase gave one major and two minor bands after staining with Coomassie Blue. The purified enzyme gave straight line kinetics in Lineweaver-Burk plots and a Km = 0.510 mM and V = 0.236 mumol/min. Fatty acid supplementation of A. laidlawii membranes had negligible effect on the membrane-bound or ethanol-extracted dehydrogenase, but substantiated the values of the Km and V. Purification, however, altered the constants by 2-4-fold, suggesting that alteration of the microenvironment or fragmentation of the dehydrogenase was significant. The purified dehydrogenase was very susceptible to a rapid inhibition was much slower (90 min) and less complete. Consideration of published purification procedures of NADH dehydrogenase strongly suggested that the purified A. laidlawii respiratory chian-linked NADH dehydrogenase was over 90% pure and certainly one of the most purified respiratory chain-linked bacterial NADH dehydrogenases.
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PMID:Purification of the reduced nicotinamide adenine dinucleotide dehydrogenase from membranes of Acholeplasma laidlawii. 99 Mar 15

A highly purified preparation of NADH dehydrogenase was isolated from bacteria M. lysodeikticus membranes. The purification procedure involved extraction of the enzyme complex from isolated membranes by EDTA, solubilization of the complex by non-ionogenic detergent (1% Triton X-100), chromatography on DEAE-cellulose and electrofocussing in the pH gradient 4-6. The isoelectric point of the preparation is at 4.5; its main component is a protein with m.w. of about 76.000.
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PMID:[Proteins of bacterial membranes. Purification of NADH-dehydrogenase by electrofocusing]. 103 Jun 33

An Escherichia coli mutant (tolI) previously shown to be tolerant to colicins Ia and Ib is defective in several functions of the bacterial cytoplasmic membrane. When compared with its parental strain, X36, whole cells of tolI show reduced rates of respiration with succinate, malate, or lactate as the substrate but near-normal rates with glucose or glycerol. Cell membrane preparations prepared from tolI cells exhibit reduced succinate and D-lactate oxidase activity but elevated levels of reduced-form nicotinamide adenine dinucleotide (NADH) oxidase. tolI cells have reduced levels of succinate and D-lactate dehydrogenase but normal levels of NADH dehydrogenase. Glycerol-grown tolI cells and membrane vesicles prepared from such cells are defective in the active transport of several amino acids and thiomethyl-beta-D-galactoside; however, they accumulate higher levels of alpha-methylglucoside when compared with X36 whole cells or vesicles. Although tolI cells adsorb less colicin Ia at high colicin concentrations than do X36 cells, it is shown that the adsorption of an Ia molecule to tolI cells has a lower probability of eliciting cell death than does Ia adsorption to strain X36 cells. It is concluded that a single mutation can lead to an alteration in several aspects of cytoplasmic membrane function and colicin I sensitivity.
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PMID:Alterations in membrane function in an Escherichia coli mutant tolerant to colicins Ia and Ib. 110 88

Both lidocaine and anoxia inhibit rapid axonal transport. In an attempt to elucidate the mechanism of this action of lidocaine, its effect on mitochondrial respiration was studies. The local anesthetic produces a dose-dependent inhibition of oxygen consumption (50 per cent inhibition at 8mM) by porcine brain mitochondria when glutamate, but not when succinate, serves as the substrate. This indicates electron transport is blocked at the NADH dehydrogenase level. Potent uncoupling of oxidative phosphorylation is observed with both substrates. All of the effects are readily reversible upon removal of the anesthetic. It is concluded that lidocaine apparently inhibits rapid axonal transport by depressing oxidative metabolism.
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PMID:Lidocaine effects on brain mitochondrial metabolism in vitro. 113 Jul 42

Intact but fragile mitochondria were isolated from unsporulated oocysts of Eimeria tenella. The mitochondria respired in response to succinate, malate plus pyruvate, and L-ascorbate at rates of 1.00, 0.40, and 0.25 mu1 O2/min/mg protein, respectively. Spectrophotometric analyses of the cytochromes in mitochondria and whole oocysts revealed b-type and o-type cytochromes, at roughly similar levels, but no cytochrome c could be detected. The mitochondrial respiration was inhibited by cyanide, azide, carbon monoxide, antimycin A, and 2-heptyl-4-hydroxyquinoline-N-oxide, but was relatively resistant to rotenone and amytal. The quinolone coccidiostats buquinolate, amquinate, methyl benzoquate, and decoquinate were identified as very powerful inhibitiors of succinate and malate plus pyruvate supported respiration in E. tenella mitochondria. None of these four drugs exhibited any inhibitory effect on chicken liver mitochondria. Only 3 pmol of the quinolones per mg mitochondrial protein was needed to achieve 50% inhibition. The inhibition could not be reversed by coenzymes Q6 or Q10. Since the quinolones did not affect L-ascorbate-supported respiration or the activities of submitochondrial succinate dehydrogenase and NADH dehydrogenase, the site of action of the quinolone coccidiostats was tentatively identified as probably near cytochrome b in E. tenella mitochondria. Mitochondria isolated from an E. tenella amquinate-resistant mutant were much less susceptible to quinolone coccidiostats; 50% inhibition was attained by 300 pmol of the drugs/mg mitochondrial protein. The results suggest that the mechanisms of action of quinolone coccidiostats is by inhibiting the cytochrome-mediated electron transport in the mitochondria of coccidia. 2-Hydroxynaphthoquinone coccidiostats were identified as inhibitors of mitochondrial respiration of both E. tenella and chicken liver. They inhibited submitochondrial succinate dehydrogenase and NADH dehydrogenase of E. tenella, and remained equally active against the mitochondrial function of E. tenella amquinolate-resistant mutant.
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PMID:Studies of the mitochondria from Eimeria tenella and inhibition of the electron transport by quinolone coccidiostats. 117 97

Cytophotometric measurements of the activities of 5 enzymes (succinate, malate, and NAD+-linked isocitrate dehydrogenases from the tricarboxylic cycle, lactate dehydrogenase from the Embden-Meyerhof pathway, and NADH dehydrogenase) were correlated with cell volume for neurones in the anterior horn of rabbit lumbar and cervical spinal cord. The data for succinate and isocitrate dehydrogenases indicated that these enzymes were at higher concentrations in the smaller neurones, which consist largely of interneurones. No preferential localization to particular sizes of cell could be assigned to the other enzymes studied. The relationship between enzyme distribution patterns and their possible role in contributing toward susceptibility to ischaemia of particular sizes of neurones is discussed.
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PMID:Quantitative oxidative enzyme histochemistry of the spinal cord. Part 2. Relation of cell size and enzyme activity to vulnerability to ischaemia. 117 87

Salivary glands of Drosophila hydei recovering from an anaerobic treatment show a significant increase in apparent Vmax of mitochondrial NADH dehydrogenase. This increase in Vmax is based on an increase in enzyme molecules resulting from synthesis de novo in the cytoplasm, as indicated by the inhibition by cycloheximide of both the increase in apparent Vmax and the increase in amino acid incorporation into enzyme fractions. The increase in enzyme activity is also inhibited by actinomycin D, which is in support of previous data indicating a casual relationship between transcription in puff 4-81B in the polytene chromosomes and an increase in apparent Vmax of the enzyme. Gel electrophoresis of mitochondrial protein extracts revealed three protein fractions with NADH dehydrogenase activity. All three fractions showed increased activity as well as increased amino acid labelling in glands recovering from anaerobiosis compared with control glands. The data suggest that the increase in mitochondrial NADH dehydrogenase activity in salivary glands recovering from an anaerobic treatment depends on increased gene transcription.
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PMID:Induced transcription-dependent synthesis of mitochondrial reduced nicotinamide-adenine dinucleotide dehydrogenase in Drosophila. 121 23

Preparations with a selectively decreased (by 85-90%) content of NADH dehydrogenase were isolated by means of heating treatment of M. lysodeikticus isolated membranes. The degree of the reduction of the NADH dehydrogenase nearest neighbour in the respiration chain of cytochrome b556 in heated membranes is similar to that in intact membranes. It is concluded that cytochrome b556 and (or) NADH dehydrogenase are capable to lateral migration in the membrane of M. lysodeikticus, resulting in the inter-chain electrone transport. A coefficient of their lateral diffusion is calculated (D equals 8-10(-10)-2-10(-9) CM2SEC-1 At 30 degrees C) on the basis of kinetics of cytochrome reduction by NADH dehydrogenase. The electron transport, due to a diffusion of respiration carriers from one assambly to another, proceeds 100 times as slow as the electrone transport in the respiratory chain. The data obtained allow to consider the aggregation of respiration enzymes as a dynamic formation.
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PMID:[Lateral diffusion of the protein components of the respiratory assembly of Microsoccus lysodeikticus]. 121 62

In isolated plant mitochondria the oxidation of both succinate and exogenous NADH responded in the expected manner to the addition of ADP or uncoupling agents, and the uncoupled rate of respiration was often in excess of the rate obtained in the presence of ADP. However, the oxidation of NAD+-linked substrates responded in a much more complex manner to the addition of ADP or uncoupling agents such as carbonyl cyanide p-trifluoromethoxyphenylhydrazone to mitochondria oxidizing pyruvate plus malate failed to result in a reliable stimulation; this uncoupled rate could be stimulated by adding AMP or ADP in the presence of oligomycin or bongkrekic acid. Spectrophometric measurements showed that the addition of AMP or ADP resulted in the simultaneous oxidation of endogenous nicotinamide nucleotide and the reduction of cytochrome b. ADP was only effective in bringing about these changes in redox state in the presence of Mg2+ whereas AMP did not require Mg2+. It was concluded that AMP activated the flow of electrons from endogenous nicotinamide nucleotide to cytochrome b, possible at the level of the internal NADH dehydrogenase.
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PMID:The activation of non-phosphorylating electron transport by adenine nucleotides in Jerusalem-artichoke (Helianthus tuberosus) mitochondria. 122 6

In the subcommissural organ (SCO) of the guinea pig, rat, golden hamster, and mouse the activity and distribution of enzymes related to the energy-supplying metabolism and of some marker enzymes of different cell organelles have been investigated by means of mostly modified histochemical methods. The results were compared with findings in the ciliated ependyma of the ventricular wall and with those in the ependyma of the choroid plexus of the third ventricle. In the ependymal part of the SCO only a moderate activity of hexokinase is observed in its specialized columnar cells whereas a high activity is present both in the ciliated ependyma and the choroid plexus. - The staining pattern of glucose-6-phosphatase is similar to that of hexokinase but this enzyme is found is the SCO only. - Likewise hexokinase, glycogen granules and enzymes related to glycogen metabolism (phosphoglucomutase, uridine-diphosphoglucose pyrophosphorylase, glycogen synthetase and phosphorylase) are regularly found most numerous and active in the nuclear and supra-nuclear area of the ependymal part. These enzymes are less active in both the other ependymal regions. - Uridine-diphosphoglucose dehydrogenase could not be demonstrated in the SCO. The NADP-linked enzymes of the pentose phosphate shunt, glucose-6-phosphate and 6-phosphogluconate dehydrogenase, show a moderate activity which decreases also from the nuclear towards the apical area of the ependymal cells of the SCO. Enzymes of the glycolytic pathway, such as glucosephosphate isomerase, fructose-6-phosphate kinase, fructose-I,6-diphosphate aldolase, glyceraldehyde-3-phosphate and lactate dehydrogenase, are highly active in the SCO and are located mainly in the supranuclear area, too. Fructose-1,6-diphosphatase could not be demonstrated thus indicating that in the SCO the pathway is most probably only glycolytic but not gluconeogenetic. Compared to the ependyma of the ventricular wall and of the choroid plexus, in the SCO the M type subunits of lactate dehydrogenase predominate. Glycolytic enzymes are also very active in the choroid plexus but less in the ciliated ependyma. Compared to the ciliated ependyma and especially to the ependyma of the choroid plexus, the activities of enzymes which are only present in mitochondria (NAD-linked isocitrate dehydrogenase, succinate dehydrogenase, NAD-linked malate dehydrogenase after preextraction, cytochrome oxidase, 3-hydroxybutyrate and glycerolphosphate and glutamate dehydrogenase) are relatively low. Mitochondria are accumulated near the superior pole of the nuclei as well as in the most apical part of the ependymal cells. - The staining pattern of NADP-linked isocitrate and malate dehydrogenase as well as of NADH dehydrogenase suggests that these enzymes are localized both in and out of mitochondria. The extramitochondrial activity of the first two enzymes might be localized in the cytosol. The extramitochondrial activity of NADH dehydrogenase might be localized in the endoplasmic reticulum...
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PMID:Enzymatic organization of the subcommissural organ. 123 49


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