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)

During aerobic growth on glucose, Escherichia coli produces acetate in the so-called overflow metabolism. DNA microarray analysis was used to determine the global gene expression patterns of chemostat cultivations of E. coli MG1655 that were characterized by different acetate formation rates during aerobic growth on glucose. A correlation analysis identified that expression of ten genes (sdhCDAB, sucB, sucC, acnB, lpdA, fumC and mdh) encoding the TCA cycle enzymes succinate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinyl-CoA synthetase, aconitase, fumarase and malate dehydrogenase, respectively, and of the acs-yjcH-actP operon for acetate utilization correlated negatively with acetate formation. Relieving transcriptional control of the sdhCDAB-b0725-sucABCD operon by chromosomal promoter exchange mutagenesis yielded a strain with increased specific activities of the TCA cycle enzymes succinate dehydrogenase, alpha-ketoglutarate dehydrogenase and succinyl-CoA synthetase, which are encoded by this operon. The resulting strain produced less acetate and directed more carbon towards carbon dioxide formation than the parent strain MG1655 while maintaining high growth and glucose consumption rates.
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PMID:Global gene expression analysis of glucose overflow metabolism in Escherichia coli and reduction of aerobic acetate formation. 1727 55

The present study investigated the protective efficacy of the novel preparation named as Kalpaamruthaa (KA, includes Semecarpus anacardium Linn nut milk extract (SA), dried powder of Phyllanthus emblica fruit and honey) on the peroxidative damage and abnormal antioxidant levels in the hepatic mitochondrial fraction of 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary carcinoma rats. Female Sprague-Dawley rats of weight 180+/-10 g were categorized into six groups. Three groups were administered DMBA (25 mg/rat dissolved in olive oil, orally) to induce mammary carcinoma. One of these groups received KA treatment (300 mg/kg b.wt., orally) and other group received SA (200 mg/kg b.wt., orally) for 14 days after 90 days of DMBA induction. Vehicle-treated control and drug control groups were also included. The hepatic mitochondrial fraction of untreated DMBA rats showed 2.96-fold increase in MDA content when compared to control rats and abnormal changes in the activities/levels of mitochondrial enzymic (superoxide dismutase, glutathione peroxidase and glutathione reductase) and non-enzymic (glutathione, vitamin C and vitamin E) antioxidants were observed. DMBA-treated rats also showed decline in the activities of mitochondrial enzymes such as succinate dehydrogenase, alpha-ketoglutarate dehydrogenase, malate dehydrogenase and isocitrate dehydrogenase. In contrast, rats treated with SA and KA showed normal lipid peroxidation antioxidant defenses and mitochondrial enzymes, thereby showing the protection rendered by SA and KA. Although, KA treatment exhibited more profound effect in inhibiting DMBA-induced oxidative stress than sole SA treatment. Results of the study indicate that the anticarcinogenic activity of KA during DMBA-initiated mammary carcinogenesis is mediated through alteration of hepatic antioxidant status as well as modulation of TCA cycle enzymes. On the basis of the observed results, KA can be considered as a readily accessible, promising and novel cancer chemopreventive agent.
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PMID:Alteration of DMBA-induced oxidative stress by additive action of a modified indigenous preparation--Kalpaamruthaa. 1734 85

Germline mutations in nuclear genes encoding mitochondrial enzymes fumarate hydratase (FH) and succinate dehydrogenase (subunits SDHB/C/D) have been implicated in the development of tumor syndromes referred to as hereditary leiomyomatosis and renal cell cancer (HLRCC) and hereditary paragangliomatosis (HPGL), respectively. FH and SDH are operating in the tricarboxylic acid cycle (the TCA cycle, the Krebs cycle). In the FH and SDH deficient tumors, accumulation of the substrates, fumarate and succinate, has been shown to cause stabilization of hypoxia inducible factor 1 alpha (HIF1 alpha). According to recent studies, HIF1 alpha could contribute to the hypoxia induced genomic instability seen in many cancers, through repression of mismatch repair (MMR) protein MSH2. In this study, in agreement with previous works, we found HIF1 alpha to be moderately or highly stabilized in 67% (16/24) and 77% (48/62) of HLRCC tumors and SDHB/C/D paragangliomas (PGL) and pheochromocytomas (PHEO), respectively. In addition, a set of 54 other familial and nonfamilial PGLs/PHEOs were studied. Moderately or highly stabilized HIF1 alpha was present in 68% (26/38) of the PGLs but in PHEOs (n = 16) no such pattern was observed. We then analyzed the suggested link between HIF1 alpha stabilization and MSH2 repression, in HLRCC and HPGL tumor material. No microsatellite instability (MSI) or lack of MSH2 expression was, however, observed. Thus we failed to provide in vivo evidence for the proposed link between HIF1 alpha stabilization and functional MMR deficiency, in TCAC deficient tumors.
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PMID:Increased HIF1 alpha in SDH and FH deficient tumors does not cause microsatellite instability. 1752 Jun 77

Mitochondria are an important intracellular source and target of reactive oxygen species. The life span of a species is thought to be determined, in part, by the rate of mitochondrial damage inflicted by oxygen free radicals during the course of normal cellular metabolism. In the present study, we have investigated the protective effect of squalene supplementation for 15 days and 30 days on energy status and antioxidant defense system in liver mitochondria of 18 young and 18 aged rats. The dietary supplementation of 2% squalene significantly minimized aging associated alterations in mitochondrial energy status by maintaining the activities of TCA cycle enzymes (isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase and malate dehydrogenase) and respiratory marker enzymes (NADH dehydrogenase and cytochrome-c-oxidase) at higher level in the liver mitochondria of aged rats compared with unsupplemented controls. It exerted an antioxidant effect by inhibiting mitochondrial lipid peroxidation (malondialdehyde) in liver of young and aged rats. Supplementation with squalene also maintained the mitochondrial antioxidant defense system at higher rate by increasing the level of reduced glutathione and the activities of glutathione-dependent antioxidant enzymes (glutathione peroxidase and glutathione-S-transferase) and antiperoxidative enzymes (superoxide dismutase and catalase) in the liver of young and aged rats. The results of this study provide evidence that dietary supplementation with squalene can improve liver mitochondrial function during aging and minimize the age-associated disorders in which reactive oxygen species are a major cause.
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PMID:Protective effect of dietary squalene supplementation on mitochondrial function in liver of aged rats. 1757 27

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

Relative levels of many individual proteins in Escherichia coli HB101 strains with 0, 37, 56, and 240 plasmids per chromosome were determined by computer image analysis of two-dimensional gel electrophoresis patterns. The plasmids investigated had very similar sequences except for small domains encoding the repressor of plasmid replication. At the intermediate plasmid copy number of 56, levels of several of the TCA cycle enzymes (oxoglutarate dehydrogenase complex, succinate thiokinase, and succinate dehydrogenase) as well as in aspartate transcarbamoylase increased. At a plasmid copy number of 240, higher amounts of PEP carboxylase as well as several of the heat shock proteins were observed. Furthermore, at high plasmid levels, significant decreases occurred in growth rate, pyruvate kinase I, pyruvate dehydrogenase complex, unadenylated glutamine synthetase, aspartate transcarbamoylase as well as in several of the proteins involved in translation. Decreases in ribosome content as well as in the free 30S and 50S ribosomal subunit pool fractions were also observed in separate analyses. These results indicate that recombinant DNA manipulations can cause major alterations in numerous host cell properties which could significantly influence cloned protein production or metabolic engineering endeavors.
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PMID:Plasmid presence changes the relative levels of many host cell proteins and ribosome components in recombinant Escherichia coli. 1860 Jun 70

In order to improve the production of succinate and malate by the filamentous fungus Aspergillus niger the activity of the glyoxylate bypass pathway was increased by over-expression of the isocitrate lyase (icl) gene. The hypothesis was that when isocitrate lyase was up-regulated the flux towards glyoxylate would increase, leading to excess formation of malate and succinate compared to the wild-type. However,metabolic network analysis showed that an increased icl expression did not result in an increased glyoxylate bypass flux. The analysis did show a global response with respect to gene expression, leading to an increased flux through the oxidative part of the TCA cycle. Instead of an increased production of succinate and malate, a major increase in fumarate production was observed. The effect of malonate, a competitive inhibitor of succinate dehydrogenase (SDH), on the physiological behaviour of the cells was investigated. Inhibition of SDH was expected to lead to succinate production, but this was not observed. There was an increase in citrate and oxalate production in the wild-type strain. Further more, in the strain with over-expression of icl the organic acid production shifted from fumarate towards malate production when malonate was added to the cultivation medium. Overall,the icl over-expression and malonate addition had a significant impact on metabolism and on organic acid production profiles. Although the expected succinate and malate formation was not observed, a distinct and interesting production of fumarate and malate was found.
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PMID:Overexpression of isocitrate lyase-glyoxylate bypass influence on metabolism in Aspergillus niger. 1927 Dec 67

A labeling scheme is introduced that facilitates the measurement of accurate (13)C(beta) chemical shifts of invisible, excited states of proteins by relaxation dispersion NMR spectroscopy. The approach makes use of protein over-expression in a strain of E. coli in which the TCA cycle enzyme succinate dehydrogenase is knocked out, leading to the production of samples with high levels of (13)C enrichment (30-40%) at C(beta) side-chain carbon positions for 15 of the amino acids with little (13)C label at positions one bond removed (approximately 5%). A pair of samples are produced using [1-(13)C]-glucose/NaH(12)CO(3) or [2-(13)C]-glucose as carbon sources with isolated and enriched (>30%) (13)C(beta) positions for 11 and 4 residues, respectively. The efficacy of the labeling procedure is established by NMR spectroscopy. The utility of such samples for measurement of (13)C(beta) chemical shifts of invisible, excited states in exchange with visible, ground conformations is confirmed by relaxation dispersion studies of a protein-ligand binding exchange reaction in which the extracted chemical shift differences from dispersion profiles compare favorably with those obtained directly from measurements on ligand free and fully bound protein samples.
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PMID:Measuring 13Cbeta chemical shifts of invisible excited states in proteins by relaxation dispersion NMR spectroscopy. 1944 76

We previously demonstrated that spare respiratory capacity of the TCA cycle enzyme alpha-ketoglutarate dehydrogenase (KGDH) was completely abolished upon increasing levels of MAO-B activity in a dopaminergic cell model system (Kumar et al., J Biol Chem 278:46432-46439, 2003). MAO-B mediated increases in H(2)O(2) also appeared to result in direct oxidative inhibition of both mitochondrial complex I and aconitase. In order to elucidate the contribution that each of these components exerts over metabolic respiratory control as well as the impact of MAO-B elevation on their spare respiratory capacities, we performed metabolic respiratory control analysis. In addition to KGDH, we assessed the activities and substrate-mediated respiration of complex I, pyruvate dehydrogenase (PDH), succinate dehydrogenase (SDH), and mitochondrial aconitase in the absence and presence of complex-specific inhibitors in specific and mixed substrate conditions in mitochondria from our MAO-B elevated cells versus controls. Data from this study indicates that Complex I and KGDH are the most sensitive to inhibition by MAO-B mediated H(2)O(2) generation, and could be instrumental in determining the fate of mitochondrial metabolism in this cellular PD model system.
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PMID:Metabolic control analysis in a cellular model of elevated MAO-B: relevance to Parkinson's disease. 1952 85

Complex II (succinate-ubiquinone reductase; SQR) is a mitochondrial respiratory chain enzyme that is directly involved in the TCA cycle. Complex II exerts a reverse reaction, fumarate reductase (FRD) activity, in various species such as bacteria, parasitic helminths and shellfish, but the existence of FRD activity in humans has not been previously reported. Here, we describe the detection of FRD activity in human cancer cells. The activity level was low, but distinct, and it increased significantly when the cells were cultured under hypoxic and glucose-deprived conditions. Treatment with phosphatase caused the dephosphorylation of flavoprotein subunit (Fp) with a concomitant increase in SQR activity, whereas FRD activity decreased. On the other hand, treatment with protein kinase caused an increase in FRD activity and a decrease in SQR activity. These data suggest that modification of the Fp subunit regulates both the SQR and FRD activities of complex II and that the phosphorylation of Fp might be important for maintaining mitochondrial energy metabolism within the tumor microenvironment.
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PMID:Regulation of succinate-ubiquinone reductase and fumarate reductase activities in human complex II by phosphorylation of its flavoprotein subunit. 1964 26


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