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)

A simple and efficient osmotic lysis method was developed for enzyme studies in spiroplasmas. Log phase cells in R2 medium were harvested by centrifugation (19,600 x g for 30 min). Wash buffer supplemented with 0.23 M sucrose maintained the helicity of spiroplasma cells during washing. Osmotic lysis of spiroplasmas was achieved in H buffer that contained no sucrose. Sucrose at concentrations as low as 0.004 M dramatically increased the resistance of the spiroplasmas to osmotic lysis. NADH oxidase, lactate dehydrogenase, and malate dehydrogenase were detected in cell lysates of Spiroplasma floricola (23-6), Spiroplasma citri (R8A2), Spiroplasma apis (SR 3), and Spiroplasma melliferum (AS 576). Citrate synthase, aconitase, isocitrate dehydrogenase, alpha-ketoglutarate dehydrogenase, succinyl coenzyme A synthetase, succinate dehydrogenase, and fumarase were not detected in cell lysates of S. floricola (23-6). NADH oxidase and malate dehydrogenase were found in the cytosol whereas lactate dehydrogenase was loosely associated with the cytomembrane.
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PMID:The osmotic lysis of Spiroplasma cells and its use in enzyme studies. 795 12

Because we believe that macrophage-derived nitric oxide contributes to pathology of demyelinating diseases, we have determined the differential effects of nitric oxide on primary rat glial cells in vitro. Enriched cultures of microglia, astrocytes and oligodendrocytes were treated with S-nitroso,N-acetyl-DL-penicillamine, a nitric oxide-releasing chemical. There was a significantly decreased function of one of the ferrosulfur-containing mitochondrial enzymes after S-nitroso,N-acetyl-DL-penicillamine/nitric oxide treatment in oligodendrocytes and astrocytes compared to microglia, which were much less sensitive to S-nitroso,N-acetyl-DL-penicillamine/nitric oxide at all concentrations. At 0.5 mM S-nitroso,N-acetyl-DL-penicillamine/nitric oxide, astrocytes and oligodendrocytes suffered a 40% loss in succinate dehydrogenase activity, while microglia were unaffected. A control non-ferrosulfur-containing mitochondrial enzyme, isocitrate dehydrogenase, was not affected in any glial cell type. Although the per cent of mitochondrial damage in oligodendrocytes and astrocytes was the same for all concentrations of S-nitroso,N-acetyl-DL-penicillamine/nitric oxide, significant cell death occurred in oligodendrocytes at 1.0 mM; at this concentration there was no significant killing of microglia or astrocytes. Furthermore, at a 0.5 mM concentration of S-nitroso,N-acetyl-DL-penicillamine/nitric oxide, which inhibited mitochondrial respiration but did not kill oligodendrocytes, significant changes in oligodendrocyte morphology (e.g. retraction of processes) occurred. Morphological changes were not seen in microglia and astrocytes at any concentration of S-nitroso,N-acetyl-DL-penicillamine/nitric oxide. In addition, oligodendrocytes were more sensitive to S-nitroso,N-acetyl-DL-penicillamine/nitric oxide-induced single stranded DNA breaks than microglia or astrocytes. The mitochondrial damage was attributable to nitric oxide since N-acetyl-DL-penicillamine had no effect. Oxyhemoglobin, which competitively inhibits toxic effects of nitric oxide, protected these glial cells from mitochondrial damage, single stranded breaks in DNA and cell death in a time- and dose-dependent manner. Once again, oligodendrocytes were less easily rescued from nitric oxide effects by oxyhemoglobin than were astrocytes, suggesting greater vulnerability of the myelin-producing cell to nitric oxide. These findings suggest that there is differential sensitivity of glial cells to nitric oxide. Although oligodendrocytes and astrocytes are equally susceptible to nitric oxide-induced mitochondrial damage, oligodendrocytes are more sensitive to nitric oxide-induced single stranded DNA breaks, morphological changes and cell death. Compared to both oligodendrocytes and astrocytes, microglia, nitric oxide-producing cells, are resistant to nitric oxide-induced damage.
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PMID:Nitric oxide as a potential pathological mechanism in demyelination: its differential effects on primary glial cells in vitro. 796 31

Adult male Sprague-Dawley rats (> or = 180 days old) develop an obesity-exacerbated insulin resistance in contrast with female animals of the same strain. Given the fact the maintenance of muscle mass requires an adequate supply of insulin and active insulin receptors, we postulated that gender differences might exist in both protein content and metabolic properties of skeletal and cardiac muscle in adult Sprague-Dawley rats. Therefore, to test this hypothesis, we examined activities of bioenergetic enzymes and total protein content in the diaphragm, the heart and the plantaris muscle in 12-month-old male and female animals. Mean (+/- SD) body weights of male animals were significantly (P < 0.05) greater than female animals (598 +/- 8 vs. 362 +/- 19 g) and the diaphragm weight/body weight ratio was significantly lower in males compared to females (2.36 +/- 0.05 vs. 3.02 +/- 0.13 mg/g). The activities of isocitrate dehydrogenase (NADP-specific) and succinate dehydrogenase were significantly lower (P < 0.05) in male animals compared to females in both the crural and costal regions of the diaphragm, the heart, and the plantaris muscle. In contrast, no gender differences (P > 0.05) existed in lactate dehydrogenase activity in any of the muscles studied. Finally, muscle protein concentration was significantly higher in female animals when compared to males (P < 0.05) in all muscles studied except the heart. These data support the hypothesis that gender differences exist for adult Sprague-Dawley rats in general and specific protein content of the diaphragm, locomotor muscles, and the heart.
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PMID:Gender differences in diaphragmatic metabolic properties of the adult Sprague-Dawley rat. 797 31

The activities of 6 dehydrogenases, lactate dehydrogenase (LDH), glucose-6-phosphate dehydrogenase (G6PDH), isocitrate dehydrogenase (ICDH), glycerol-3-phosphate dehydrogenase (GDH), succinate dehydrogenase (SDH) and glutamate dehydrogenase (GLDH), determined by means of flow cytometry in 13 primary human gastrointestinal tumour cell lines, including 10 esophageal carcinomas, one gastric cancer, and 2 pancreatic cancers. Two-parametric measurements of specific dehydrogenase activities in single cells were performed with DAPI as fluorochrome for the nuclear DNA and with the fluorescent redox system of 5-cyano-2,3-ditolyl-tetrazolium chloride (CTC) which forms brilliant red formazan crystals upon reduction by cellular redox enzymes. Furthermore, with the aid of the calibration procedure reported previously [18] the enzyme activities were expressed as biochemical units. This application of tetrazolium salt technique for demonstrating dehydrogenase activities in human tumour cells by flow cytometry offers an alternative tool to characterize malignant tumors.
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PMID:Flow-cytometric determination of dehydrogenase activities in primary human gastrointestinal tumor cell lines. 816

NADP(+)-specific isocitrate dehydrogenase (ICDH-NADP: EC 1 x 1 x 1 x 42) is primarily a mitochondrial matrix enzyme in both mammalian skeletal muscle and heart and has markedly higher activity levels than the NAD(+)-specific isozyme. To date, it is unknown whether ICDH-NADP activity is inducible with in vivo exercise training in locomotor or respiratory skeletal muscle. Therefore, the purpose of this investigation was to quantify alterations in ICDH-NADP activity in respiratory muscles (costal and crural diaphragm) and locomotor muscles (medial gastrocnemius, plantaris and soleus) following 8 weeks of treadmill endurance training. Ten of the animals had been assigned randomly to an exercise group (TR) and had completed 8 weeks of progressive (5 days week-1: 45 min day-1) treadmill endurance training while the remaining 10 animals comprised a sedentary control (C). Mean ICDH-NADP activities in Tr were significantly higher (P < 0.05) when compared with C in the medial gastrocnemius (61.3%), plantaris (42.9%) soleus (21.4%). Mean costal diaphragm ICDH-NADP activity noted in trained animals when compared to the sedentary control group was not significantly higher (10.8% greater for TR; P = 0.14). No mean differences (P = 0.58) were noted in the crural diaphragm. The results indicate that ICDH-NADP is inducible with endurance training in locomotor skeletal muscle. A coefficient of determination of 0.624 (i.e. 62.4% of the variance could be explained) for ICDH-NADP was calculated, with the oxidative enzyme marker succinate dehydrogenase (P < 0.05) indicating a positive, moderate relationship.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inducibility of NADP-specific isocitrate dehydrogenase with endurance training in skeletal muscle. 826 7

Flow cytometric measurements of the activities of lactate dehydrogenase, glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, glycerol-3-phosphate dehydrogenase, succinate dehydrogenase and glutamate dehydrogenase in single Ehrlich ascites tumour cells are described using a tetrazolium salt/fluorescent formazan reaction. Applying cyano-ditolyl-tetrazolium chloride (CTC) as redox dye indicating enzyme reaction, and DAPI as a fluorochrome for nuclear DNA staining, the bivariate flow cytometric assay of enzyme activity and cell cycle analysis was established. Furthermore, adopting the calibration procedure reported formerly, consisting of biochemical determination and flow cytometry of the same sample performed parallelly, the enzyme activities were expressed in biochemical units. The dehydrogenase activities found in Ehrlich ascites cells were 97.5 fmol H2 per average positive cell during 5 min for lactate dehydrogenase, 69.0, 10.6, 25.3, 29.7, and 19.0 fmol H2 per average positive cell during 20 min for glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, glycerol-3-phosphate dehydrogenase, succinate dehydrogenase and glutamate dehydrogenase, respectively. This quantitative procedure can offer an alternative analytic tool for enzyme cytology.
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PMID:Enzyme activities of six different dehydrogenases in Ehrlich ascites cells measured by flow cytometry. 835 66

Succinate dehydrogenase activity was measured in rat pancreatic islet homogenates incubated in the presence of [1,4-14C]succinate, the reaction velocity being judged through the generation of 14CO2 in the auxiliary reactions catalysed by pig heart fumarase and chicken liver NADP-malate dehydrogenase. In the presence of 1.0 mM succinate, the reaction velocity averaged 5.53 +/- 0.44 pmol min-1 microgram-1 islet protein. The Km for succinate was close to 0.4 mM and the enzymic activity was restricted to mitochondria. These kinetic results indicate that, under the present experimental conditions, the activity of succinate dehydrogenase does not vastly exceed that of either NAD-isocitrate dehydrogenase or the 2-ketoglutarate dehydrogenase complex, at least when the latter enzymes are activated by ADP and/or Ca2+. Nevertheless, the activity of succinate dehydrogenase is sufficient to account for the increase in O2 uptake evoked in intact islets by the monomethyl ester of succinic acid. It could become a rate-limiting step of the Krebs cycle in models of B-cell dysfunction.
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PMID:Hexose metabolism in pancreatic islets: succinate dehydrogenase activity in islet homogenates. 840 29

Activities of the tricarboxylic acid cycle enzymes were measured in subcellular fractions of liver from rats that had been fed clofibrate for 3 weeks. Large changes in these activities per gram tissue were found in the large particle fraction, which also showed an increase in total protein concentration of 76% under clofibrate treatment. The three regulatory enzymes of the cycle, namely citrate synthase, NAD(+)-linked isocitrate dehydrogenase, and 2-oxoglutarate dehydrogenase were significantly enhanced by 24% (P < 0.02), 54% (P < 0.02), and 153% (P < 0.005), respectively. Fumarase and malate dehydrogenase rose by 71% (P < 0.005) and 95% (P < 0.02), whereas succinate dehydrogenase remained unchanged. Enhancement of the citrate synthase, NAD-isocitrate dehydrogenase, and 2-oxoglutarate dehydrogenase may play a role in decreasing intracellular availability of acetyl-CoA for lipid metabolism.
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PMID:Clofibrate elevates enzyme activities of the tricarboxylic acid cycle in rat liver. 846 21

Using two-dimensional gel electrophoresis and N-terminal amino acid sequencing analysis, we demonstrate that a mutant of the global regulatory protein ArcA fails to decrease the synthesis of the TCA cycle enzymes malate dehydrogenase, isocitrate dehydrogenase, lipoamide dehydrogenase E3 and succinate dehydrogenase in response to stasis, while the increased production of the glycolysis enzymes phosphoglycerate mutase and pyruvate kinase is unaffected. Microcalorimetric and respiratory measurements show that the continued production of TCA cycle enzymes in the (delta)arcA mutant is manifested as an elevated rate of respiration and total metabolic activity during starvation. The (delta)arcA mutant is severely impaired in surviving prolonged periods of exogenous carbon starvation, a phenotype that can be alleviated by overproducing the superoxide dismutase SodA. In addition, flow cytometry demonstrates that starving (delta)arcA mutant cells, in contrast to wild-type cells, fail to perform reductive division, remain large and contain multiple chromosomal copies. We suggest that the ArcA-dependent reduced production of electron donors and the decreased level and activity of the aerobic respiratory apparatus during growth arrest is an integral part of a defense system aimed at avoiding the damaging effects of oxygen radicals and controlling the rate of utilization of endogenous reserves.
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PMID:Bacterial defense against aging: role of the Escherichia coli ArcA regulator in gene expression, readjusted energy flux and survival during stasis. 867 Aug 22

In this study, we compared metronidazole (Mtz)-sensitive and -resistant strains of Helicobacter pylori for metabolic differences that might correlate with drug resistance. Included in this study was an isogenic Mtz(r) strain, HP1107, that was constructed by transforming genomic DNA from Mtz(r) strain HP439 into Mtz(s) strain HP500. Enzyme activities were also measured for Mtz(r) strains grown in the presence or absence of 18 micrograms of metronidazole per ml (ca. one-half of the MIC). These studies confirmed the presence of the Embden-Meyerhof-Parnas, Entner-Doudoroff, and pentose pathways. H. pylori strains expressed enzymatic activities indicative of a complete and active Krebs cycle. All strains expressed pyruvate oxidoreductase (POR) and alpha-ketoglutarate oxidoreductase (KOR) as measured with the redox-active dye benzyl viologen (30 to 96 nmol/min/mg of protein for POR and 30 nmol/min/mg of protein for KOR). When grown in the presence of Mtz at > or = 3.5 micrograms/ml, Mtz(r) strains expressed no detectable POR or KOR activity. The apparent repression of POR and KOR activities by Mtz affected bacterial growth as manifest by extended lag periods and growth yield reductions of > 30%. A dose-dependent relationship was demonstrated between the metronidazole concentration in the growth medium and the specific activity of POR measured in bacterial cell extracts. The observed repression was not due to inactivation of POR by Mtz. In addition to repression of POR and KOR activities, growth in the presence of Mtz also led to decreases in the activities of various Krebs cycle enzymes, including aconitase, isocitrate dehydrogenase and succinate dehydrogenase. All of the Mtz(r) strains examined expressed isocitrate lyase and malate synthase activities indicative of the glyoxylate bypass. No isocitrate lyase activity was detected in Mtz(s) strain HP500. Isocitrate lyase activity was expressed by HP500 following transformation to Mtz resistance (Mtz(r) strain HP1107) with DNA from an Mtz(r) strain. The results of this study suggest that Mtz resistance may be a recessive trait, possibly involving inactivation of a regulatory gene, that results in constitutive expression of isocitrate lyase. Repression of POR and KOR activities in response to low levels of Mtz may be a general response of H. pylori strains to Mtz, but only resistant strains manage to survive via activation of compensatory metabolic pathways.
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PMID:Metabolic activities of metronidazole-sensitive and -resistant strains of Helicobacter pylori: repression of pyruvate oxidoreductase and expression of isocitrate lyase activity correlate with resistance. 875 44


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