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 activities of five mitochondrial enzymes tested in liver from patients with Reye's syndrome were measured. Citrate synthase, glutamic dehydrogenase, succinic dehydrogenase, pyruvate carboxylase, and pyruvate dehydrogenase were all outside of the range shown by control samples and well below them in activity. The activity of two extramitochondrial enzymes, glucose-6-phosphatase, which is a microsomal enzyme, and fructose-1,6-diphosphatase, which is a soluble enzyme, were in the normal range in samples from Reye's syndrome patients. In both muscle and brain the activities of the mitochondrial enzyme, citrate synthase, glutamic dehydrogenase, and succinic dehydrogenase were all within the control range. Pyruvate dehydrogenase was found to be normal in muscle from these patients.
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PMID:Reye's syndrome: preservation of mitochondrial enzymes in brain and muscle compared with liver. 21 43

Phosphate-activated glutaminase, glutamic acid decarboxylase, pyruvate dehydrogenase, succinic dehydrogenase, pH, and lactate were measured in frontal cortex and caudate nucleus of postmortem brains from cases of Alzheimer-type dementia (ATD), Down's syndrome, Huntington's disease, and one case of Pick's disease, as well as from sudden death and agonal controls. Lactate levels were higher and pH, phosphate-activated glutaminase, and glutamic acid decarboxylase levels were lower in the agonal controls than in the sudden death controls. Phosphate-activated glutaminase and glutamic acid decarboxylase were correlated with tissue pH and lactate, and also were reduced by in vitro acidification, suggesting that the low activities of these enzymes in agonal controls were related to decreased pH consequent upon lactate accumulation. Compared with control tissues at the same pH, phosphate-activated glutaminase and glutamic acid decarboxylase were unaltered in ATD and Down's frontal cortex and reduced in Huntington's caudate nucleus, and glutamic acid decarboxylase was reduced in Huntington's frontal cortex. These data suggest that GABAergic neurons are not affected in ATD and confirm the GABAergic defect in Huntington's disease. Pyruvate dehydrogenase and succinic dehydrogenase activities were the same in agonal controls and sudden death controls and were unaffected by acid pH and lactate in vitro, and pyruvate dehydrogenase was not correlated with pH or lactate. Reduced pyruvate dehydrogenase in frontal cortex of individual ATD, Down's, and Pick's cases, and in the caudate nucleus of Huntington's and Down's cases, was accompanied by gliosis/neuron loss. We conclude that decreased pyruvate dehydrogenase reflects neuronal loss.
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PMID:Enzyme activities in relation to pH and lactate in postmortem brain in Alzheimer-type and other dementias. 221 15

The activity of alpha-ketoglutarate dehydrogenase and succinic dehydrogenase in readaptation after 15-day hypokinesia was within normal limits, whereas following 30-day hypokinesia it was enhanced on days 11-15. Pyruvate dehydrogenase exhibited hyperactivity in the end of readaptation week 2 both in 15- and 30-day hypokinesia which resulted in rat liver hyperactivity of glutamate dehydrogenase and transaminases. Normal levels of the latter were recorded on readaptation day 12-19.
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PMID:[Activity of various oxidases and transaminases in the rat liver in the readaptation period after hypokinesia up to 30 days]. 232 62

Considerable variations were found in the in vitro effect of alloxan on mouse liver enzymes associated with the citric acid cycle. The following approximative alloxan concentrations induced 50% inhibition of enzyme activity: 10(-6)M for aconitase, 10(-4)M for NAD-linked isocitrate dehydrogenase, glutamate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinyl-CoA synthetase and fumarase, and 10(-3)M for citrate synthase and NADP-linked isocitrate dehydrogenase. Pyruvate dehydrogenase, succinate dehydrogenase and malate dehydrogenase were not inhibited by 10(-3)M alloxan. The inhibition of aconitase was competitive both when using mouse liver and purified porcine heart enzyme. The Ki values for the purified enzyme in the presence of 5 microM alloxan were 0.22 microM with citrate, 4.0 microM with cis-aconitate and 0.62 microM with isocitrate as substrate. The high sensitivity of aconitase for inhibition by alloxan probably plays a prominent role for the toxic effects of alloxan.
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PMID:Inhibition by alloxan of mitochondrial aconitase and other enzymes associated with the citric acid cycle. 651 May 22

The chronic toxic effects of chromium (2.6 mg/1) on the carbohydrate metabolism of a teleost fish, Channa punctatus were examined after 60 and 120 days of exposure. After 60 days the lactic acid content of blood and muscles was increased but liver lactic acid content decreased. Liver glycogen was also depleted. The activity of lactate dehydrogenase was inhibited in liver and kidney. Pyruvate dehydrogenase and succinate dehydrogenase activities were also inhibited in all the tissues except muscles. Fish were hypoglycemic and hyperlactemic after 120 days of exposure to chromium. The glycogen content increased in liver but decreased in muscles. Lactate dehydrogenase activity was inhibited in all the six tissues. The activity of pyruvate dehydrogenase decreased in liver, intestine, gill and muscles. In muscles succinate dehydrogenase activity was elevated but inhibition was recorded in other tissues.
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PMID:Enzymological and biochemical changes produced by chronic chromium exposure in a teleost fish, Channa punctatus. 683 20

Cytokines such as tumor necrosis factor alpha (TNF alpha) and Interleukin-1alpha (IL1alpha) are known to influence energy metabolism and mitochondrial function in tumor and vascular smooth muscle cells. The aim of the present study was to investigate whether in cardiomyocytes mitochondrial function and PDH activity may also be impaired by TNF alpha and IL1alpha. Pyruvate dehydrogenase (PDH) activity and mitochondrial oxygen consumption of cultured cardiomyocytes were determined after subchronic exposure (24 h) to TNF alpha (1, 10, 100, 1000 I.U./ml) and IL1alpha (0.1, 1, 10, 100 I.U./ml). TNF alpha- and IL1alpha- exposure of the cardiomyocytes resulted in a concentration dependent decrease of PDH activity up to 38%. In parallel, selective oxygen consumption of the respiratory chain complexes I (NADH:ubiquinone oxidoreductase) and II (succinate:ubiquinone oxidoreductase) decreased by up to 45%. Addition of the PDH activator dichloracetate (0.01 M) resulted in complete restoration of PDH activity but not of mitochondrial function. The results suggest a primary inhibition of the mitochondrial respiratory chain by TNF alpha and IL1alpha and a subsequent down regulation of PDH activity.
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PMID:TNF-alpha and IL-1 alpha inhibit both pyruvate dehydrogenase activity and mitochondrial function in cardiomyocytes: evidence for primary impairment of mitochondrial function. 945 Jun 46

In dementia of Alzheimer type (DAT), cerebral glucose metabolism is reduced in vivo, and enzymes involved in glucose breakdown are impaired in post-mortem brain tissue. Pyruvate dehydrogenase complex activity (PDHc) is one of the enzymes known to be reduced, while succinate dehydrogenase activity (SDH), another enzyme of oxidative glucose metabolism is unchanged. In dementia of vascular type (DVT), variable changes in glucose metabolism have been demonstrated in vivo, while changes of enzyme activities in post-mortem brain tissue are unknown. Here, PDHc and SDH activity were stimulated with each of the two stereoisomers of alpha lipoic acid in post-mortem parietal brain cortex of patients with DAT, DVT, and one case of Pick's disease and compared to stimulation effects in a control group, matched for age, sex, post-mortem delay, and storage time of brain tissue. PDHc in DAT and DVT, but not in Pick's disease was reduced. PDHc activity could be slightly stimulated by 10 micro M of the physiological stereoisomer (r)-alpha-lipoic acid, in controls and DVT (possibly also in Pick's disease), but not in DAT. In all groups investigated SDH was activated by 100 micro M and 1 mM of both isomers of alpha-lipoic acid, whereas 10 mM of both stereoisomers of alpha-lipoic acid caused an inhibition of both, PDHc and SDH activity. The loss of basal and of (r)-alpha-lipoic acid stimulated PDHc activity indicate that a functional or structural impairment of PDHc may exist in DAT and DVT which is not merely attributable to loss of mitochondria since basal and stimulated SDH activities are similar in controls, DVT and DAT, thus indicating selective vulnerability of PDHc.
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PMID:(r)-, but not (s)-alpha lipoic acid stimulates deficient brain pyruvate dehydrogenase complex in vascular dementia, but not in Alzheimer dementia. 1499 56

The pyruvate dehydrogenase complex from pea (Pisum sativum L.) mitochondria was purified 23-fold by high speed centrifugation and glycerol gradient fractionation. The complex had a s(20,w) of 47.5S but this is a minimal value since the complex is unstable. The complex is specific for NAD(+) and pyruvate; NADP(+) and other keto acids give no reaction. Mg(2+), thiamine pyrophosphate, and cysteine are also required for maximal activity. The pH optimum for the complex was between 6.5 and 7.5.Continuous sucrose density gradients were used to separate castor bean (Ricinus communis L.) endosperm proplastids from mitochondria. Pyruvate dehydrogenase complex activity was found to be coincident with the proplastid peak on all of the gradients. Some separation of proplastids and mitochondria could be achieved by differential centrifugation and the ratios of the activities of the pyruvate dehydrogenase complex to succinic dehydrogenase and acetyl-CoA carboxylase to succinic dehydrogenase were consistent with both the pyruvate dehydrogenase complex and acetyl-CoA carboxylase being present in the proplastid. The proplastid fraction has to be treated with a detergent, Triton X-100, before maximal activity of the pyruvate dehydrogenase complex activity is expressed, indicating that it is bound in the organelle. The complex had a sharp pH optimum of 7.5. The complex required added Mg(2+), cysteine, and thiamine pyrophosphate for maximal activity but thiamine pyrophosphate was inhibitory at higher concentrations.
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PMID:Pyruvate dehydrogenase complex from higher plant mitochondria and proplastids. 1665 53

In this study yeast cell physiological activity was assessed on the basis of the in situ activity of two important enzymes, succinate dehydrogenase and pyruvate decarboxylase. FUN1 dye bioconversion and cellular ATP content were also taken as important indicators of yeast cell activity. The study was conducted on six brewing yeast strains, which were either free cells or immobilized on a chamotte carrier. The experimental data obtained indicate clearly that, in most cases, the immobilized cells showed lower enzyme activity than free cells from analogous cultures. Pyruvate decarboxylase activity in immobilized cells was higher than in planktonic cell populations only in the case of the Saccharomyces pastorianus 680 strain. However, in a comparative assessment of the fermentation process, conducted with the use of free and immobilized cells, much more favorable dynamics and carbon dioxide productivity were observed in immobilized cells, especially in the case of brewing lager yeast strains. This may explain the higher total cell density per volume unit of the fermented medium and the improved resistance of immobilized cells to environmental changes.
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PMID:Physiological tests for yeast brewery cells immobilized on modified chamotte carrier. 2388 84

Multiple Mitochondrial Dysfunction Syndrome (MMDS) comprises a group of severe autosomal recessive diseases with onset in early infancy and characterized by a systemic disorder of energy metabolism, resulting in weakness, respiratory failure, lack of neurological development, lactic acidosis, and early death. Biochemical findings include defects of complexes I, II, and III of the mitochondrial respiratory chain and severe deficiency of Pyruvate dehydrogenase complex (PDHc). Three genes have been associated with MMDS since now: NFU1, BOLA3, and IBA57. We describe an Italian male patient presenting with severe psychomotor regression after an infectious episode, lactic acidosis, hyperglycinemia, reduction of respiratory chain complex II associated with a marked deficiency of PDHc activity. He carried two heterozygous mutations in NFU1, one novel (p.Cys210Phe) and one previously reported (p.Gly189Arg) missense change affecting highly conserved residues. A severe leukoencephalopathy with cavitations in deep white matter was disclosed at brain MRI, suggesting a peculiar neuroradiological phenotype associated with defect in this gene.
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PMID:Cavitating leukoencephalopathy with multiple mitochondrial dysfunction syndrome and NFU1 mutations. 2547 4


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