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)

Activities of succinate oxidase, fumarate reductase (FR) and succinate dehydrogenase (SDH) under a set of defined conditions were determined in the mitochondrial isolate from Setaria digitata, the filarial parasite from the cattle Bos indicus. Presence of only two activities namely SDH and succinate--UQ reductase of the succinate oxidase system could be detected in S. digitata. In the absence of cytochromes, the 3rd enzyme of the complex namely cytochrome oxidase is absent and it is proposed that an alternative oxidase is responsible for completing the succinate oxidation expressed as succinate oxidase activity. Though SDH and FR catalyse reverse reactions, they responded differently to modulators such as oxaloacetate, aspartate, alanine, pyruvate and fumarate. The degree of response of the two activities against inhibitors of electron transport was also different. Interestingly fumarate caused only 50% inhibition of succinate oxidation, while the effect against FR was more convincing.
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PMID:Succinate oxidase and fumarate reductase systems of filarial parasite Setaria digitata. 1098 24

Alanine is a nutritionally nonessential amino acid synthesized by transamination of pyruvate originated from glucose. Alanine is the principal gluconeogenic amino acid because it can originate pyruvate and glucose through the inverse pathway. Considering that it has been suggested that alanine could be used as a dietary supplement in combination with growth hormone in the treatment of undernourished children affected by some inherited metabolic diseases to induce anabolism, the principal objective of the present work was to measure the activities of the mitochondrial respiratory chain complexes and succinate dehydrogenase in brain cortex of Wistar rats subjected to chronic alanine administration from the 6th to the 21st day of life. We also investigated the in vitro effect of alanine on the activities of mitochondrial respiratory chain complexes and succinate dehydrogenase in the same brain structure of 22-day-old rats. The results showed a reduction of Complex I + III and succinate dehydrogenase activities in brain cortex of rats subjected to alanine administration. We also verified that alanine inhibited the in vitro activity of Complexes I + III by competition with NADH. These results indicate that more investigation would be necessary before considering alanine supplementation as a valid adjuvant therapy to sick children with these disorders.
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PMID:Inhibition of the mitochondrial respiratory chain by alanine in rat cerebral cortex. 1232 82

The effect of surangin B, an insecticidal natural product coumarin, on presynaptic release of endogenous amino acids was investigated using a purified synaptosomal fraction isolated from mouse brain. Surangin B stimulated the release of glutamic acid (GLU), gamma-aminobutyric acid (GABA), serine, alanine and the aminosulfonic acid taurine from synaptosomes at micromolar concentrations. In all cases, these responses were reduced by removing calcium from the saline and surangin B-evoked release of GLU, GABA, aspartic acid (ASP) and alanine was significantly inhibited by the sodium channel blocker tetrodotoxin. Rotenone (a complex I inhibitor) and carbonyl cyanide chlorophenylhydrazone (CCCP; an uncoupler), were more potent releasers of amino acids from synaptosomes than surangin B, however, carboxin (a complex II-selective inhibitor), was extremely weak to ineffective in this regard. The stimulatory effect of surangin B and complex III-selective inhibitors on release of GLU, GABA, ASP and alanine by synaptosomes was significantly reduced by N,N,N',N'-tetramethyl-p-phenylenediamine, suggesting that blockade of complex III in intraterminal mitochondria is an important effect of this coumarin. Our results demonstrate that surangin B, in common with CCCP and inhibitors of complex I and III, cause release of both neurotransmitter and non-neurotransmitter amino acids from nerve endings in vitro. However, in contrast to most classical agents which interfere selectively with mitochondrial function, the release of endogenous amino acids from synaptosomes by surangin B also involves a moderate extracellular calcium ion-dependent component and relies partially on sodium ion entry into the nerve ending.
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PMID:Stimulation by surangin B of endogenous amino acid release from synaptosomes. 1450 34

The activities of GABA-catabolizing enzymes (GABA-transaminase and succinic semialdehyde dehydrogenase), succinate dehydrogenase, alanine and aspartate amino transferases, the contents of GABA, glutamate, glutamine, alanine, aspartate and glycine were studied in rat brain regions after acute morphine administration. Intraperitoneal (i.p.) administration of 10 mg/kg morphine increased the glutamate level and decreased GABA and glycine levels in cortex. This may explain an excitable effect of morphine. When the higher doses of morphine were administered (20 and 40 mg/kg, i.p.), the most pronounced changes in the amino acids tested were observed in brain stem, possibly because of higher density of opiate receptors there. Decrease in glutamate level in the brain stem was accompanied by accumulation of its metabolic precursors glutamine and aspartate and decrease of inhibitory amino acids (GABA, glycine) leves, when the dose of 40 mg/kg was used. The data obtained indicate a dose-dependent relationship between the parameters studied and behavioral action of morphine.
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PMID:[GABA metabolism and contents of neuroactive amino acids in rat brain after acute morphine administration]. 1585 Feb 24

The influence of chronic morphine intoxication (for 7, 14 and 21-days) has been studied on the contents of neuroactive amino acids (GABA, glutamate, glutamine, alanine, aspartate, glycine, taurine) and on the activities of their metabolizing enzymes (GABA-transaminase, succinic semialdehyde dehydrogenase, succinic dehydrogenase, alanine- and aspartate-aminotransferase) in the rat brain regions: cortex, brain stem and cerebellum. We detected the significant decrease of glutamate level and the enhancement of GABA and aspartate levels in cortex after long-term morphine administration. In brain stem the increase in the contents of GABA, glutamine and taurine was noted together with the tendency in attenuation of this effect when intoxication was prolonged. The dose-dependent enhancement in the levels of glutamate, aspartate and glycine was observed after longer courses of morphine administration. In cerebellum the 21-day morphine administration led to attenuation of the morphine-induced increase in the contents of GABA, glutamate, alanine and glycine.
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PMID:[Chronic morphine intoxication and metabolism of neuroactive amino acids in the rat brain]. 1610 92

To know the short- as well as long-term effect of aqueous latex extracts of Euphorbia tirucalli on carbohydrate and protein metabolism, the snail Lymnaea acuminata was exposed to sublethal doses of 0.37 and 0.55 mg/L for a 24-h and 0.20 and 0.31 mg/L for a 96-h exposure period. Significant (P<0.05) alterations in the glycogen, pyruvate, lactate, total protein, and free amino acid level, as well as in the activity of enzyme lactic dehydrogenase, succinic dehydrogenase, cytochrome oxidase, protease, aspartate aminotransaminase, and alanine aminotransaminase were observed in the nervous, hepatopancreatic, and ovotestis tissues of the freshwater vector snail L. acuminata exposed to sublethal doses of E. tirucalli latex extract. The alterations in all biochemical parameters were significantly (P<0.05) time and dose dependent. After the 7th day of the withdrawal of treatment, there was significant (P<0.05) recovery in glycogen, pyruvate, lactate, total protein, and the free amino acid level and in the activity of the lactic dehydrogenase, succinic dehydrogenase, cytochrome oxidase, protease, aspartate aminotransaminase and alanine aminotransaminase enzymes in all three of the studied tissues of the snail, which supports the view that the plant product is safe for use as a molluscicide for the control of harmful freshwater vector snails in the aquatic environment.
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PMID:Alterations in carbohydrates and the protein metabolism of the harmful freshwater vector snail Lymnaea acuminata induced by the Euphorbia tirucalli latex extract. 1630 80

The Escherichia coli complex II homologues succinate:ubiquinone oxidoreductase (SQR, SdhCDAB) and menaquinol:fumarate oxidoreductase (QFR, FrdABCD) have remarkable structural homology at their dicarboxylate binding sites. Although both SQR and QFR can catalyze the interconversion of fumarate and succinate, QFR is a much better fumarate reductase, and SQR is a better succinate oxidase. An exception to the conservation of amino acids near the dicarboxylate binding sites of the two enzymes is that there is a Glu (FrdA Glu-49) near the covalently bound FAD cofactor in most QFRs, which is replaced with a Gln (SdhA Gln-50) in SQRs. The role of the amino acid side chain in enzymes with Glu/Gln/Ala substitutions at FrdA Glu-49 and SdhA Gln-50 has been investigated in this study. The data demonstrate that the mutant enzymes with Ala substitutions in either QFR or SQR remain functionally similar to their wild type counterparts. There were, however, dramatic changes in the catalytic properties when Glu and Gln were exchanged for each other in QFR and SQR. The data show that QFR and SQR enzymes are more efficient succinate oxidases when Gln is in the target position and a better fumarate reductase when Glu is present. Overall, structural and catalytic analyses of the FrdA E49Q and SdhA Q50E mutants suggest that coulombic effects and the electronic state of the FAD are critical in dictating the preferred directionality of the succinate/fumarate interconversions catalyzed by the complex II superfamily.
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PMID:Fumarate reductase and succinate oxidase activity of Escherichia coli complex II homologs are perturbed differently by mutation of the flavin binding domain. 1648 32

The reversible modification of Atg8 with phosphatidylethanolamine (PE) is crucial for autophagy, the bulk degradation process of cytoplasmic components by the vacuolar/lysosomal system. Atg4 is a cysteine protease that is responsible for the processing and deconjugation of Atg8. Human Atg4B (HsAtg4B; a mammalian orthologue of yeast Atg4) and LC3 (a mammalian orthologue of yeast Atg8) were expressed and purified and two complexes, one consisting of HsAtg4B(1-354) and LC3(1-120) (complex I; the product complex) and the other consisting of HsAtg4B(1-354) and LC3(1-124) (complex II; the substrate complex), were crystallized using polyethylene glycol 3350 as a precipitant. In both complexes His280 of HsAtg4B was mutated to alanine. The crystals belong to the same space group P2(1)2(1)2(1), with unit-cell parameters a = 47.5, b = 91.8, c = 102.6 A for complex I and a = 46.9, b = 90.9, c = 102.5 A for complex II. Diffraction data were collected to a resolution of 1.9 A from both crystals.
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PMID:Crystallization and preliminary crystallographic analysis of human Atg4B-LC3 complex. 1727 49

The coupling of succinate oxidation to the reduction of ubiquinone by succinate dehydrogenase (SDH) constitutes a pivotal reaction in the aerobic generation of energy. In Saccharomyces cerevisiae, SDH is a tetramer composed of a catalytic dimer comprising a flavoprotein subunit, Sdh1p and an iron-sulfur protein, Sdh2p and a heme b-containing membrane-anchoring dimer comprising the Sdh3p and Sdh4p subunits. In order to investigate the role of heme in SDH catalysis, we constructed an S. cerevisiae strain expressing a mutant enzyme lacking the two heme axial ligands, Sdh3p His-106 and Sdh4p Cys-78. The mutant enzyme was characterized for growth on a non-fermentable carbon source, for enzyme assembly, for succinate-dependent quinone reduction and for its heme b content. Replacement of both Sdh3p His-106 and Sdh4p Cys-78 with alanine residues leads to an undetectable level of cytochrome b(562). Although enzyme assembly is slightly impaired, the apocytochrome SDH retains a significant ability to reduce quinone. The enzyme has a reduced affinity for quinone and its catalytic efficiency is reduced by an order of magnitude. To better understand the effects of the mutations, we employed atomistic molecular dynamic simulations to investigate the enzyme's structure and stability in the absence of heme. Our results strongly suggest that heme is not required for electron transport from succinate to quinone nor is it necessary for assembly of the S. cerevisiae SDH.
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PMID:The Saccharomyces cerevisiae succinate dehydrogenase does not require heme for ubiquinone reduction. 1802 69

The changes in the neuroactive amino acid contents, GABA metabolism and TCA reactions have been studied in rat brain regions under experimental morphine withdrawal (MW). MW was developed by means of the cessation of morphine intraperitoneal injections 1 and 36 hours, 3 and 7 days after the course of morphine administration for 7 days. In cortex the significant increase in the contents of glutamate, glutamine, asparagine, and alanine was observed in remote terms of MW. In cerebellum MW led to the decrease in the levels of glutamine and asparagine and increase in glycine level, followed by the GABA-transaminase activation and the succinate dehydrogenase inhibition. In thalamus prolongation of MW caused to the further inhibition of the activities of the GABA-catabolising enzymes. The changes observed in the amino acids levels and the GABA shunt activity are likely to be explained by indirect adaptation of the brain regions differing in the opioid receptors contents to protracted morphine administration.
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PMID:[GABA metabolism and neuroactive amino acids in the rat brain in morphine withdrawal syndrome]. 1803 23


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