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)

Incubation of chromate with isolated rat liver submitochondrial particles under anaerobic conditions in vitro results in reduction of chromium(VI) and formation of chromium(V). In the presence of NADH, submitochondrial particles (SMPs) were active in reducing chromate as shown by UV-vis spectroscopic studies, and forming a chromium(V) species which was detectable by electron paramagnetic resonance spectroscopy. In the presence of succinate, SMPs were less effective in reducing chromate and forming chromium(V) relative to their NADH-dependent activity. However, SMPs showed a higher rate of oxygen depletion with NADH as compared to succinate as substrate, suggesting that differences in the NADH-dependent versus succinate-dependent chromate-reductase activity of SMPs is probably due to differences in efficiency of electron donation by succinate and NADH. The use of specific electron transport chain inhibitors allowed the sites of chromium(VI) reduction and chromium(V) formation in SMPs to be determined. Rotenone, antimycin and cyanide all produced approximately 40% inhibition of the NADH-dependent chromate-reductase activity. Thus, complex I (NADH:ubiquinone oxidoreductase) appears to be responsible for the inhibitor-insensitive, and complex IV (ferrocytochrome c:oxygen oxidoreductase) for the inhibitor-sensitive NADH-dependent chromium(VI) reduction and chromium(V) formation. Cyanide and antimycin produced approximately 50% inhibition of the succinate-dependent chromate-reductase activity of SMPs, while no detectable inhibition was observed with rotenone. These results confirm the chromate-reductase activity of complex IV, and suggest that complex II (succinate:ubiquinone oxidoreductase) is responsible for the inhibitor-insensitive succinate-dependent chromate-reductase activity of SMPs. Since chromium(VI) is effectively metabolized by electron transport chain complexes of the mitochondrial inner membrane in vitro, and chromium(V) is formed as an intermediate in the process, mitochondria may play a role in chromium(VI) carcinogenesis.
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PMID:Chromium(V) is produced upon reduction of chromate by mitochondrial electron transport chain complexes. 253 17

The case of a 24 years-old woman with weakness since the teens and progressive loss of muscle strength is reported. The muscle biopsy showed increased number of mitochondria. In two occasions the respiratory chain enzymes showed important reduction of the succinate-cytochrome-C-reductase, suggesting a possible defect in the complex II of the respiratory chain. Large doses of vitamins C and K were prescribed. There was improvement of muscle strength. A discussion about the most common syndromes marked by mitochondrial abnormalities in muscle is made, as well as about the type of work-up that should be done in suspect cases of respiratory chain defects.
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PMID:[Myopathy due to succinate cytochrome C oxidoreductase deficiency: possible defect of complex II of the respiratory chain]. 256 40

Ragged-red fibers (RRFs) are mainly seen in mitochondrial myopathy and related to biochemical defects in electron transfer chain on some occasions. Recently, some papers reported the occurrence of RRFs in the biopsied muscle of myotonic dystrophy (MyD). To examine whether the mitochondrial function is disturbed in MyD, we have studied the biopsied muscles of 12 cases with MyD (10 males and 2 females averaging 38 years of age) morphologically and mainly biochemically. RRFs, ranging from 2--20% of the muscle fibers, were identified in 5 out of 12 cases. On electron microscopy, these fibers had aggregated abnormally enlarged mitochondria with dene bodies, concentrically whirled membranous cristae and paracrystalline inclusions. Clinically, 4 of 5 cases with RRFs had mild to moderate and only 2 of 7 without RRFs had ophthalmoplegia. Bicycle ergometer exercise test showed abnormal increase of lactate/pyruvate ratio in three cases with RRFs. Histochemically, cytochrome c oxidase (CCO) activity was absent selectively in all of the RRFs. Immunohistochemical staining showed the presence of CCO protein by using monoclonal antibody which was specific to CCO subunit IV. Biochemical study with crude muscle extract of 11 cases of MyD showed decreases in NADH dehydrogenase, NADH CoQ reductase, succinate CoQ reductase (SCR), CCO, carnitine actyl transferase activities in most of cases regardless RRFs. To avoid the influence possibly derived from the various stages of muscle degeneration in the biopsied specimens, we calculated the ratio of the enzyme activities compared with succinate dehydrogenase which was located in the electron transfer chain and did not show any statistical difference regardless of RRFs.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[A study of mitochondrial electron transfer chain in myotonic dystrophy]. 259 36

The effects of tetragalloylglucose (1,2,3,6-tetra-O-galloyl-beta-D-glucose) on purified complex II (succinate-ubiquinone oxidoreductase) of the mitochondrial electron transport system of Ascaris muscle were studied. Both succinate-ubiquinone-1 (Q1) oxidoreductase, and succinate dehydrogenase measured with 3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide (MTT) in the presence of phenazine methosulfate (PMS) were inhibited by tetragalloylglucose. The inhibitions of both reductase activities of complex II were of competitive type, and the inhibitor constant (Ki) for Ascaris complex II (148 nM) was lower than that for rat liver complex II (1.5 microM). Thus, Ascaris complex II is much more sensitive to this inhibitor than the mammalian counterpart.
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PMID:Inhibitory effects of tetragalloylglucose on the complex II of mitochondrial respiratory chain of Ascaris muscle. 260 4

Fumarate reductase of Escherichia coli is converted to a deactivated state when tightly bound by oxaloacetate (OAA). Incubation of the inhibited enzyme with anions or reduction of the enzyme by substrate restores both the activity of the enzyme and its sensitivity to thiol reagents. In these respects the enzyme behaves like cardiac succinate dehydrogenase. Close to an order of magnitude difference was found to exist between the affinities of OAA for the oxidized (KD approximately 0.12 microM) and reduced (KD approximately 0.9 microM) forms of fumarate reductase. Redox titrations of deactivated fumarate reductase preparations have confirmed that reductive activation, as in cardiac succinate dehydrogenase (B. A. C. Ackrell, E. B. Kearney, and D. Edmondson (1975) J. Biol. Chem. 250, 7114-7119), is the result of reduction of the covalently bound FAD moiety and not the non-heme iron clusters of the enzyme. However, the processes differed for the two enzymes; activation of fumarate reductase involved 2e- and 1H+, consistent with reduction of the flavin to the anionic hydroquinone form, whereas the process requires 2e- and 2H+ in cardiac succinate dehydrogenase. The reason for the difference is not known. The redox potential of the FAD/FADH2 couple in FRD (Em approximately -55 mV) was also slightly more positive than that in cardiac succinate dehydrogenase (-90 mV).
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PMID:Interactions of oxaloacetate with Escherichia coli fumarate reductase. 264 83

The subcellular distribution patterns of aromatase, 5 alpha- and 5 beta-reductase in the hypothalamus/preoptic area of Japanese quail were studied using standard methods of centrifugation, and fractional constituents were identified by marker enzymes. Aromatase was concentrated 8-fold in the 100,000 g pellet (P3) along with a 3-fold enrichment in the microsomal marker NADPH-cytochrome c reductase (NCR) a result consistent with glandular tissues. In addition, aromatase was enriched 2-fold in the 11,000 g pellet (P2) and, owing to its large size, this fraction accounted for more total activity than P3. Although P2 contained the mitochondrial marker succinate dehydrogenase (SDH), treatment with Triton X-100 to solubilize membranes and release occluded enzymes increased measured NCR and the cytosol marker lactate dehydrogenase (LDH) 2- and 4-fold, respectively--evidence that this fraction was composed of mitochondria plus synaptosomes (pinched-off nerve terminals). To further explore the location of aromatase in the 11,000 g fraction, P2 was exposed to hypotonic buffer, a treatment known to cause lysis of synaptosomes, and then separated into three fractions P2a (11,000 g pellet), P2b (100,000 g pellet) and P2s (100,000 g supernatant). Aromatase colocalized with the microsomal marker NCR (13- and 4-fold increase, respectively) in the 100,000 g (P2b) pellet which was, however, devoid of mitochondrial enzyme activity. We infer from this that a significant portion of aromatase in brain is associated with smooth membranes present inside synaptosomes. 5 beta-Reductase in quail brain subfractions was enriched 6-fold in the 100,000 g supernatant together with a 4-fold enrichment in the cytosolic marker LDH.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Localization of aromatase in synaptosomal and microsomal subfractions of quail (Coturnix coturnix japonica) brain. 271 59

Extreme endurance training was used to investigate the adaptability of the rat diaphragm muscle fibers. During the final phase of the 14-wk training program, the animals were running for 240 min/day at an estimated requirement of 80% of pretraining maximal O2 consumption. Analysis of a sample of the costal diaphragm indicated that training resulted in a 34% reduction (P less than 0.05) in the percent distribution of type IIa fibers [27.7 +/- 1.1 vs. 18.3 +/- 2.6 (SE)] and a 15% increase (P less than 0.05) in the percent of type IIb fibers (40.0 +/- 1.2 vs. 46.1 +/- 2.4). No change (P greater than 0.05) was found in the distribution of the type I fibers (32.3 +/- 1.2 vs. 35.7 +/- 1.3). Oxidative potential as assessed with NADH-tetrazolium reductase and measured microphotometrically increased (P less than 0.05) by 19% in type I fibers but did not change in either the type IIa or type IIb fibers. No effect of training was found when a different oxidative marker, succinic dehydrogenase, was employed. Similarly glycolytic potential based on the activity of alpha-glycerophosphate dehydrogenase was not affected by training. Glycogen concentration was elevated by 60% (P less than 0.01) in type I fibers and 77% (P less than 0.01) in type IIb fibers with training but was not altered (P greater than 0.05) in type IIa fibers. Reductions (P less than 0.05) in fiber area ranging from 11 to 20% were observed in all fiber types as a result of training, whereas the number of capillaries per fiber remained static.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Extreme endurance training and fiber type adaptation in rat diaphragm. 273 83

Intensities of histochemical and immunohistochemical reactions in muscle fibres of Rana and Xenopus have been estimated microphotometrically, and the data from serial sections statically analysed. Quantitative validities of reactions and measurements have also been assessed against independent published evidence. It is concluded that NADH-tetrazolium reductase overestimates tonic-fibre aerobic capacities and the actomyosin ATPase reaction overestimates their contraction speeds. However, it appears that succinate dehydrogenase, despite being a near-equilibrium enzyme of particulate distribution, indicates the relative aerobic capacities of fibres with acceptable accuracy when lightly reacted. Capacities for aerobic and anaerobic metabolism are positively correlated over all types of fibre (r typically approximately 0.6 for 200 fibres), perhaps as an adaptation to environmental hypoxia. Multivariate clusters (indicating fibre types) have been sought, using Ward's method with optimizing procedures (iterative relocation and multivariate-normal modelling). Cluster analysis confirms the subjective identifications of two 'slow/tonic' types in Xenopus (labelled T5 and S4) but of only one (T5) in Rana. Division of the 'fast family' twitch fibres into three types (F1-F3) in both genera, with metabolic capacity related inversely to apparent shortening velocity, is highly supportable by objective criteria. However, statistically significant subdivisions also present themselves. Rana F2 and Xenopus F1 clusters can be bisected according to metabolic capacity; and Xenopus F2 fibres fall into three subtypes reflecting different isomyosin contents. In the different types of twitch fibre, ratios of myofibrillar ATP consumption rate to aerobic capacity increase up to 30-fold with contraction speed, but anaerobic/aerobic ratios do so only 5-fold.
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PMID:Quantitative analysis of histochemical and immunohistochemical reactions in skeletal muscle fibres of Rana and Xenopus. 280 82

Myeloperoxidase, a granule-associated enzyme of neutrophils and monocytes, combines with H2O2 and chloride to form a potent microbicidal system that contributes to phagocyte antimicrobial activity. The nature of the lesion or lesions induced by the myeloperoxidase system which are responsible for the loss of microbial replicative activity (viability) remains unknown. Using Escherichia coli grown to late log or stationary phase under conditions of low aeration with succinate as the sole carbon source, we found that myeloperoxidase-induced loss of microbial viability could be correlated with a decrease in succinate-dependent respiration (succinate oxidase activity). Succinate dehydrogenase activity fell rapidly to undetectable levels during incubation with the myeloperoxidase system, suggesting that damage to the dehydrogenase was a major factor in the loss of oxidase activity. Other components of the succinate oxidase system were resistant to the actions of myeloperoxidase. The ubiquinone-8 and cytochrome components of the respiratory chain remained nearly constant in amount despite reduction of respiration to undetectable levels. However, as expected from the loss of succinate dehydrogenase activity, succinate-ubiquinone reductase and succinate-cytochrome reductase activities were markedly impaired. We propose that the loss of E. coli viability induced by the myeloperoxidase-H2O2-chloride system is due in part to the loss of electron transport function consequent to the oxidation of critical catalytic centers in susceptible dehydrogenases.
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PMID:Myeloperoxidase-mediated damage to the succinate oxidase system of Escherichia coli. Evidence for selective inactivation of the dehydrogenase component. 282 9

The histochemical activities of nonspecific acid and alkaline phosphatases, NADH- and NADPH-tetrazolium reductases, alpha-glycerophosphate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase were investigated in kidneys from rats treated with lithium and lithium plus neuroleptics. During the first 8 weeks of lithium treatment the activity of NADH-tetrazolium reductase, succinate dehydrogenase and alpha-glycerophosphate dehydrogenase activity in the collecting ducts increased. The other enzymes did not change. After 8 weeks of treatment no further changes in enzyme activity occurred. Withdrawal of lithium caused normalization of enzyme activity after 8 weeks. A decrease in concentration ability was found in parallel with the increase in enzyme activities (p less than 0.001). The changes in enzyme activity were not significantly correlated to morphological changes in the collecting ducts. Treatment with neuroleptics alone caused no change in enzyme activity. During combined lithium plus neuroleptic treatment the enzyme activities changed in a similar way as during lithium therapy, but the changes were less pronounced. In parallel, a less pronounced decrease in concentration ability was found during this treatment.
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PMID:Correlation between distal nephron enzyme activity, structure and function in rats during lithium and lithium plus neuroleptic treatment. 285 95


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