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:1.3.5.1 (succinate dehydrogenase)
8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The occurrence of succinic dehydrogenase [succinic:(acceptor) oxidoreductase, EC 1.3.99.1] in membrane fractions of Micrococcus lysodeikticus was investigated. The enzyme could be purified 10-fold, by deoxycholate treatment. Butanol extraction of membranes yielded an active fraction, nonsedimentable at 130,000 x g for 2 hr and altered in its phospholipid content relative to membranes. The activity of the enzyme in particulate preparations was decreased in the presence of competitive inhibitors and by compounds known to react with iron, sulfhydryl groups, and flavine. In this respect, the bacterial succinic dehydrogenase is similar to the enzyme derived from yeast and mammalian sources. In certain membrane fractions, Ca(2+) and Mg(2+) exhibited inhibitory effects whereas Triton X-100 caused activation. The enzyme could also be activated by substrate. In the phenazine reductase assay, incomplete reduction of electron acceptor was observed upon addition of divalent cations and iron binding agents.
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PMID:Characterization of the membrane-bound succinic dehydrogenase of Micrococcus lysodeikticus. 432 10

1. Some properties of succinate dehydrogenase [succinate-(acceptor) oxidoreductase, EC 1.3.99.1] in membrane preparations from Micrococcus lysodeikticus (N.C.T.C. 2665) were investigated. 2. In the spectrophotometric assay system adopted the reaction velocity was shown to be proportional to the amount of membrane added. Dichlorophenol-indophenol, reduced photochemically in the presence of phenazine methosulphate, or enzymically by the membrane-bound enzyme, was shown to undergo reoxidation in the dark. 3. The membrane-bound enzyme was found to be inactivated at temperatures above 10 degrees C. 4. The specific activity of membrane-bound succinate dehydrogenase was found to increase between two- and three-fold in diluted membrane preparations equilibrated at 0 degrees C for 6h. Membranes treated with sodium deoxycholate showed no enzyme activation on dilution but displayed maximal activity, all activity being sedimentable at 103000g. The increase in specific activity observed on dilution could be partially inhibited by fixation with glutaraldehyde, or by the presence of bovine serum albumin. 5. The addition of Mg(2+) or Ca(2+) ions to membrane suspensions caused an overall depression of enzyme activity. 6. The results suggest the presence of an ;inhibitor' that affects the expression of membrane bound succinate dehydrogenase activity.
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PMID:Factors influencing the activity of succinate dehydrogenase in membrane preparations from Micrococcus lysodeikticus. 549 52

1. Exposure of Astasia longa to oxygen+carbon dioxide (95:5) at atmospheric pressure leads to an inhibition of growth rate and of respiration. Growth resumes at the normal rate as soon as the oxygenation is discontinued, but respiration recovers more slowly. 2. Mitochondria prepared from cells exposed to oxygen+carbon dioxide (95:5) during growth have considerably decreased activities of succinate-cytochrome c oxidoreductase, NADH-cytochrome c oxidoreductase, succinate dehydrogenase and succinate oxidase activities as compared with mitochondria obtained from cells exposed to air+carbon dioxide (95:5). Cytochrome oxidase activity is not appreciably inhibited by exposure of the cells to 95% oxygen. 3. The mitochondrial fraction of Astasia contains rhodoquinone. The rhodoquinone concentration increases in cells exposed to 95% oxygen. The content of ergosterol-containing compounds also increases in the mitochondria of cells exposed to 95% oxygen. There is little change in the ubiquinone content of the mitochondrial fraction. The ubiquinone of Astasia appears to be ubiquinone-45.
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PMID:Oxygen toxicity in Astasia. 558 20

Cells of the aerotolerant anaerobe Giardia lamblia respire in the presence of oxygen. Endogenous respiration is stimulated by glucose but not by other carbohydrates and Krebs cycle intermediates. Endogenous and glucose-stimulated respiration are insensitive to cyanide, malonate, and 2,4-dinitrophenol, but are inhibited by atabrin and iodoacetamide. G. lamblia produces ethanol, acetate and CO2 both aerobically and anaerobically either from endogenous reserves or exogenous glucose. Molecular hydrogen is not produced. The following enzyme activities were detected in homogenates: hexokinase, fructose-biphosphate aldolase, pyruvate kinase, phosphoenolpyruvate carboxykinase, malate dehydrogenase, malate dehydrogenase (decarboxylating), pyruvate synthase, acetyl-CoA synthetase, alcohol dehydrogenase (NADP+), NADH dehydrogenase, NADPH dehydrogenase, NADPH oxidoreductase and superoxide dismutase. The enzymes of energy and carbohydrate metabolism are nonsedimentable (109 000 x g for 30 min). Activities of lactate dehydrogenase, hydrogenase, phosphate acetyltransferase, acetate kinase, citrate synthase, succinate dehydrogenase, fumarate hydratase and catalase were below the limits of detection. The results suggest the occurrence of glycolysis, energy production by substrate level phosphorylation and a flavin, iron-sulfur protein mediated electron transport system as well as the absence of cytochrome mediated oxidative phosphorylation and functional Krebs cycle.
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PMID:Energy metabolism of the anaerobic protozoon Giardia lamblia. 610 7

In human foetal brain ontogeny the cerebral activity of succinate oxidoreductase (EC 1.3.99.1), i.e. succinate dehydrogenase (SDH), is higher than the cerebellar activity. With rise in foetal body weight the activity in all the brain regions gradually declines. SDH in all the brain regions shows two high-activity periods, one at 20-35 g and another at 110-220 g body weight. The enzyme exhibits a craniocaudal pattern of development. At all times of gestation, L-glutamate:ammonia ligase (EC 6.3.1.2), i.e. glutamine synthetase, activity in the spinal cord and medulla is higher than in the other three regions. At 190 g body weight glutamine synthetase shows an activity peak in all brain regions. Monoamine:oxygen oxidoreductase (EC 1.4.3.4). i.e. monoamine oxidase (MAO), is present much before the onset of electrical activity. It develops caudocranially and exhibits a biphasic pattern of development in all the regions. It increases considerably in the medulla and the spinal core towards late gestational periods.
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PMID:Succinate dehydrogenase, monoamine oxidase and glutamine synthetase in developing human foetal brain regions. 612 68

The effect of n-hexane, 2-hexanol, 5-hydroxy-2-hexanone, 2,5-hexanediol, methyl n-butyl ketone ( MnBK ) and 2,5-hexanedione (2,5-HD) has been studied in vitro on crystalline glyceraldehyde-3-phosphate dehydrogenase (GAPDH), DL-glyceraldehyde-3-phosphate: NAD oxidoreductase (phosphorylating) EC. 1.2.1.12 and phosphofructokinase (PFK) ATP: D-fructose-6-phosphate-1-phosphotransferase; EC. 2.7.1.11 and lactic dehydrogenase (LDH) L-lactate: NAD+ oxidoreductase, EC. 1.1.1.27. MnBK and 2,5-HD both inhibited GAPDH and PFK activities selectively. n-Hexane and 2-hexanol had no effect on GAPDH and PFK activities; 5-hydroxy-2-hexanone and 2,5-hexanediol exhibited a slight inhibitory effect on these enzymes. Neither metabolites of n-hexane have any effect on LDH activity. 2,5-Hexanedione did not inhibit transketolase (D-sedoheptulose-7-phosphate: D-glyceraldehyde-3-phosphate glycolaldehyde transferase, EC. 2.2.1.1) and succinate dehydrogenase (succinate: 2,6-dichlorophenol-indophenol oxidoreductase, EC. 1.3.99.1) activities. The levels of ATP were reduced in 2,5-HD-treated cat sciatic nerves and returned to normal levels by exposing the nerve to sodium pyruvate.
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PMID:In vitro effect of n-hexane and its metabolites on selected enzymes in glycolysis, pentose phosphate pathway and citric acid cycle. 623 75

I. Succinate:Q oxidoreductase (EC 1.3.99.1) as present in beef-heart submitochondrial particles contains equal amounts of FAD, a [2Fe-2S] cluster and a [4Fe-4S] cluster. Both Fe-S clusters are reducible by succinate. 2. A second type of [2Fe-2S] cluster, called center S-2, that has been proposed to be present in purified preparations of succinate dehydrogenase and isolated Complex II (Ohnishi, T., Winter, D.B., Lim, J. and King, T.E. (1973) Biochem. Biophys. Res. Commun. 53, 231--237) is an artifact introduced by the purification procedure. 3. It is suggested that the 70 000 dalton subunit which is known to bind the flavin, accomodates also the [4Fe-4S] cluster whereas the 28 000 dalton subunit contains the [2Fe-2S] cluster.
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PMID:The prosthetic groups in succinate dehydrogenase. Number and stoichiometry. 624 47

Iron-sulfur clusters present in rat liver submitochondrial particles were characterized by ESR at temperatures between 30 and 5.5 K combined with potentiometric titrations. The spectral and thermodynamic characteristics of the iron-sulfur clusters were generally similar to those previously reported for pigeon or bovine heart submitochondrial particles. Clusters N-1a, N-1b, N-2, N-3 and N-4 of NADH dehydrogenase had midpoint oxidation-reduction potentials at pH 7.5 of -425, -265, -85, -240 and -260 mV, respectively. Clusters S-1 and S-3 of succinate dehydrogenase had midpoint potentials of 0 and +65 mV, respectively. The iron-sulfur cluster of electron-transferring flavo-protein-ubiquinone oxidoreductase exhibited the gz signal at g = 2.08 and had a midpoint potential of +30 mV. This signal was relatively prominent in rat liver compared to pigeon or bovine heart. Submitochondrial particles from rats chronically treated with ethanol (36% of total calories, 40 days) showed decreases of 20-30+% in amplitudes of signals due to clusters N-2, N-3 and N-4 compared to those from pair-fed control rats. Signals from clusters N-1b, S-1, S-3 and electron-transferring flavoprotein-ubiquinone oxidoreductase were unaffected. Microwave power-saturation behavior was similar for both submitochondrial particle preparations, suggesting that the lower signal amplitudes reflected a lower content of these particular clusters. NADH dehydrogenase activity was significantly decreased (46%), whilst succinate dehydrogenase activity was elevated (25%), following chronic ethanol consumption. The results indicate that chronic ethanol treatment leads to an alteration of the structure and function of the NADH dehydrogenase segment of the electron transfer chain. This alteration is one of the factors contributing to the lower respiration rates observed following chronic ethanol administration.
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PMID:Characterization of iron-sulfur clusters in rat liver submitochondrial particles by electron paramagnetic resonance spectroscopy. Alterations produced by chronic ethanol consumption. 624 7

Local anesthetics and alcohols were found to inhibit mitochondrial electron transport at several points along the chain. THe anesthetics employed were the tertiary amines procaine, tetracaine, dibucaine, and chlorpromazine, and the alcohols were n-butamol, n-pentanol, n-hexanol, and benzyl alcohol. Uncoupled sonic submitochondrial particles from beef heart and rat liver were studied. We report the following: (1) All of the anesthetics were found to inhibit each of the segments of the electron transport chain assayed; these included cytochrome c oxidase, durohydroquinone oxidase, succinate oxidase, NADH oxidase, succinate dehydrogenase, succinate-cytochrome c oxidoreductase, and NADH-cytochrome c oxidoreductase. (2) NADH oxidase and NADH-cytochrome c oxidoreductase required the lowest concentration of anesthetic for inhibition, and cytochrome c oxidase required the highest concentrations. (3) We conclude that there are several points along the chain at which inhibition occurs, the most sensitive being in the region of Complex I (NADH dehydrogenase). (4) Beef heart submitochondrial particles are less sensitive to inhibition than are rat liver particles. (5) Low concentrations of several of the anesthetics gave enhancement of electron transport activity, whereas higher concentrations of the same agents caused inhibition. (6) The concentrations of anesthetics (alcohol and tertiary amine) which gave 50% inhibition of NADH oxidase were lower than the reported concentrations required for blockage of frog sciatic nerve.
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PMID:Multiple sites of inhibition of mitochondrial electron transport by local anesthetics. 626 99

The free radical EPR signals of ubisemiquinone in mitochondria and submitochondrial particles (SMP) were investigated. One of the signals observed under the conditions of the respiratory chain highly oxidized and characterized by an unusually short time of the spin-lattice relaxation has previously been termed as SQ-2. The intensity of SQ-2 in SMP strongly depends on pH, the maximal concentration of QH. is reached at about 8.5. The signal is absent in the succinate dehydrogenase-depleted SMP and is highly sensitive to specific inhibitors of succinate: CoQ-oxidoreductase, such as alpha-thenoyltrifluoroacetone and carboxin. In SMP SQ-2 disappears in the presence of low concentrations of ferricyanide, while in mitochondria this non-penetrating oxidant provokes the appearance of SQ-2. The data obtained suggest that SQ-2 belongs to a stable ubisemiquinone which forms a complex with a FeS center of succinate dehydrogenase, is localized at the M-side of the membrane, and is kinetically isolated from the cytochrome chain. Oxidation of the terminal segment of the respiratory chain of mitochondria and SMP reduced by succinate in the presence of antimycin, is in some cases accompanied by an appearance of a strong free radical EPR signal which is stable at 77K but disappears rapidly in the frozen samples at -30- -40 degrees C. It is suggested that the signal is generated by an antimycin-insensitive oxidation of QH2 to QH. via the branch of the respiratory chain comprised of the Rieske FeS-protein and cytochrome c1. The mechanisms of how the two-electron oxidation-reduction of CoQ is coupled with the one-electron transfer through the cytochromes and FeS centers in the respiratory chain are discussed.
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PMID:[Interaction of ubisemiquinone with succinate dehydrogenase and the cytochrome chain of mitochondria]. 629 22


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