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)

Rat liver mitochondrial enzyme activities were measured after exposing the animals to the atmospheric pressure of 380 mm Hg for 5 h and 14 days. Succinate dehydrogenase and succinate oxidase activities increased significantly during the hypoxic period of 14 days. No change was observed in cytochrome oxidase activity. Malate dehydrogenase and glutamate dehydrogenase activities increased somewhat, but not significantly. The efficiency of oxidative phosphorylation (the ADP:O ratio) in the isolated mitochondria remained unchanged. The exact mitochondrial protein values showed a 15% decrease as compared with the control group. The concentrations of cytochromes did not change significantly in the hypoxic group. During the short hypoxic period succinate dehydrogenase, succinate oxidase and cytochrome oxidase activities increased as compared with those in the control group.
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PMID:Rat liver mitochondrial enzyme activities in hypoxia. 17 Jul 95

Mitochondria isolated from spontaneous and transplanted mammary adenocarcinomas of two strains of mice were compared, by various biochemical criteria, to mitochondria from mammary glands of midpregnant or hormonally stimulated, cancer-free mice. The specific activities of several mitochondrial enzymes including cytochrome oxidase, alpha-glycerophosphate oxidase, and succinate dehydrogenase were twofold to threefold lower, whereas the activity of monoamine oxidase was two fold higher in tumor mitochondria. Malate dehydrogenase, adenylate kinase, and NADH oxidase showed similar levels of activity in tumor and midpregnant mammary gland mitochondria. In addition, mitochondrial polypeptide composition was analyzed by electrophoresis on sodium dodecyl sulfate-urea polyacrylamide gels. Midpregnant mammary gland and mammary tumor mitochondria were similar in polypeptide composition; however, several differences were observed. A high-molecular-weight polypeptide, present in mid-pregnant mammary gland mitochondria was absent from tumor mitochondria. Also, tumor mitochondria contained an additional high-molecular-weight polypeptide not found in the midpregnant mammary gland. There were numerous differences in the relative proportions of many polypeptides common to both tumor and midpregnant mammary gland mitochondria.
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PMID:Biochemical studies on mitochondria isolated from Normal and Neoplastic Tissues of the Mouse Mammary Gland. 17 82

Studies were performed in the activities of certain enzymes from oxidoreductase group: cytochrome c-oxidoreductase (EC 1.6.99.3), succinate dehydrogenase succinates: cytochrome c-oxidoreductase (EC 1.3.99.1), cytochrome oxidase (EC 1.9.3.1) and malate dehydrogenase (EC 1.1.1.37) in mitochondria from neuronal and glial-enriched fractions. The mitochondrial fraction purity was observed by the electron microscope. The enzyme activity of the glial mitochondrial fraction was much higher than that in the neuronal mitochondria. Malate dehydrogenase from glial enriched fraction consists of three isoenzymes, while neuronal mitochondria had two isoenzymes of malate dehydrogenase. The neuronal mitochondria were found to be more stable to lubrol and digitonin.
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PMID:[Differences in the enzymatic activity of mitochondria from enriched neuronal and glial fractions]. 18 84

The chronically active (pseudomyotonic) gastrocnemius muscle in the C57B16J dy2J/dy2J mouse contains both elevated lactate and glycogen as well as fibers that have high amounts of glycogen and enhanced glyconeogenic activity. In the present study we analyze the activities of some key glyconeogenic enzymes to assess the causes of elevated muscle glycogen and to determine the pathway for glycogen synthesis from lactate. Glycogen synthase, malate dehydrogenase, phosphoenolpyruvate carboxykinase, and malic enzyme were all elevated in homogenates of the chronically active muscle. Activities of glycogen phosphorylase and fructose 1,6-bisphosphatase were decreased in whole muscle homogenates. Histochemistry demonstrated that the high-glycogen fibers were typically fast-twitch glycolytic fibers that had high glycogen synthase, glycogen phosphorylase, and malic enzyme activities. Malate dehydrogenase activity followed succinate dehydrogenase activity and did not correlate to high-glycogen fibers. Thus the high-glycogen fibers have an elevated enzymatic capacity for glycogen synthesis from lactate, and the pathway may involve use of the pyruvate kinase bypass enzymes.
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PMID:Glyconeogenic and glycogenic enzymes in chronically active and normal skeletal muscle. 191 41

Malate dehydrogenase, malic enzyme, succinate dehydrogenase, and fumarate reductase activities have been studied in the cytoplasm and mitochondria of Taenia crassiceps larvae. The results show that these larvae contain enzymes for anaerobic acquisition of energy with terminal fumarate reductase, but some facts, as the high ratio of succinate dehydrogenase activity to fumarate reductase activity and the low proportion of fumarate reductase in the whole NADH oxidase activity in mitochondria, suggest that aerobic processes are also involved in the energy acquisition in this parasite.
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PMID:Malic enzyme, malate dehydrogenase, fumarate reductase and succinate dehydrogenase in the larvae of Taenia crassiceps (Zeder, 1800). 359 92

The culture of Bacillus brevis var. G-B R-form was grown in the presence of beta-phenyl-beta-alanine, the inhibitor of gramicidin S synthesis, is characterized by enhanced endogenous respiration and the DPI-reductase activity as compared to the culture synthezising antibiotic. The increased synthesis of the antibiotic in the region of the culture transition from the logarithmic growth phase to the linear one is associated with a decrease in the number of viable cells despite the fact that the culture on the whole does not die but continues to grow. The membranes prepared from young gramicidin S-free cells and from the cells enriched with the antibiotic possess identical electron micrograph images, IR spectra and protein sets as determined by polyacrylamide gel electrophoresis in a Na-DS system. However, in young cell membranes NADH and succinate dehydrogenase are insensitive to gramicidin S and only malate dehydrogenase is inhibited by this antibiotic. In aged cell membranes the activities of all mentioned dehydrogenases are suppressed. Malate dehydrogenase from young cells is weakly inhibited by thyrotrycin obtained from Bac. brevis ATCC 10068; succinate dehydrogenase is entirely insensitive to this antibiotic, while NADH-dehydrogenase is almost completely inhibited by it. The specificity of action on the respiratory chain of peptide antibiotics synthesized by the cells of one strain of Bac. brevis is suggestive of a possible regulatory role of these peptides in the metabolism of the producent. Hence the accumulation of gramicidin S which is adsorbed on the membrane and destroys the respiratory chain function to the cause of the low rate of oxygen uptake by the culture of Bac. brevis var. G-B R-form and of the low activities of DPI-reductases.
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PMID:[Structuro-functional properties of the bacteria Bacillus brevis in relation to the accumulation of gramicidin S in cells]. 619 82

Enzyme activities forming extracellular products from succinate, fumarate, and malate were examined using washed cell suspensions of Pseudomonas fluorescens from chemostat cultures. Membrane-associated enzyme activities (glucose, gluconate, and malate dehydrogenases), producing large accumulations of extracellular oxidation products in carbon-excess environments, have previously been found in P. fluorescens. Investigations carried out here have demonstrated the presence in this microorganism of a malic enzyme activity which produces extracellular pyruvate from malate in carbon-excess environments. Although the three membrane dehydrogenase enzymes decrease significantly in carbon-limited chemostat cultures, malic enzyme activity was found to increase fourfold under these conditions. The regulation of malate dehydrogenase and malic enzyme by malate or succinate was similar. Malate dehydrogenase increased and malic enzyme decreased in carbon-excess cultures. The opposite effect was observed in carbon-limited cultures. When pyruvate or glucose was used as the carbon source, malate dehydrogenase was regulated similarly by the available carbon concentration, but malic enzyme activity producing extracellular pyruvate was not detected. While large accumulations of extracellular oxalacetate and pyruvate were produced in malate-excess cultures, no extracellular oxidation products were detected in succinate-excess cultures. This may be explained by the lack of detectable activity for the conversion of added external succinate to extracellular fumarate and malate in cells from carbon-excess cultures. In cells from carbon-limited (malate or succinate) cultures, very active enzymes for the conversion of succinate to extracellular fumarate and malate were detected. Washed cell suspensions from these carbon-limited cultures rapidly oxidized added succinate to extracellular pyruvate through the sequential action of succinate dehydrogenase, fumarase, and malic enzyme. Succinate dehydrogenase and fumarase activities producing extracellular products were not detected in cells from chemostat cultures using pyruvate or glucose as the carbon source. Uptake activities for succinate, malate, and pyruvate also were found to increase in carbon-limited (malate or succinate) and decrease in carbon-excess cultures. The role of the membrane-associated enzymes forming different pathways for carbon dissimilation in both carbon-limited and carbon-excess environments is discussed.
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PMID:Membrane enzymes associated with the dissimilation of some citric acid cycle substrates and production of extracellular oxidation products in chemostat cultures of Pseudomonas fluorescens. 642 68

Microfilariae of bovine filarial parasite Setaria cervi are equipped with the enzymes of glycolysis, pentose phosphate and PEP-succinate pathways and thus resemble the adult form in its metabolic pattern. Malate dehydrogenase was the most active enzyme in microfilariae followed by lactic dehydrogenase and fumarase, while phosphoglucoisomerase, PEP-carboxykinase and FDP-aldolase were comparatively less active. The very low ratio of PK/PEPCK in S. cervi microfilariae indicates active fixation of CO2 into PEP to produce oxalacetate. Centperazine and diethylcarbamazine significantly inhibited PEP-carboxykinase, fumarate reductase and succinic dehydrogenase, suggesting that these antifilarials probably exert microfilaricidal action by blocking the PEP-succinate pathway.
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PMID:Setaria cervi: enzymes in microfilariae and in vitro action of antifilarials. 715 43

Mitochondrial function is a key determinant of both excitability and viability of neurons. Present studies were carried out to decipher cerebral mitochondrial oxidative energy metabolism and membrane function in the chronic condition of generalized seizures induced by picrotoxin (PTX) in rats. PTX-induced convulsions resulted in decreased respiration rates (14-41%) with glutamate, pyruvate + malate, and succinate as substrate. The ADP phosphorylation rates were drastically reduced by 44-65%. An opposite trend was observed with ascorbate + N,N,N',N'-tetramethyl-p-phenylenediamine [corrected] (TMPD) as substrate. In general, uncoupling of the mitochondrial electron transport was observed after PTX treatment. Malate dehydrogenase (MDH) and succinate dehydrogenase (SDH) activities were decreased by 20-80%; also, there was significant reduction in cytochrome b content after PTX treatment, while the F(o)F(1) ATPase (complex V) activity increased in basal and 2,4-dinitrophenol (DNP)-stimulated condition, indicating increased membrane fragility. The substrate kinetics analysis had shown that K(m) and V(max) of the higher affinity kinetic component of ATPase increased significantly by 1.2- to 1.4-fold in epileptic condition. Temperature kinetic analysis revealed 1.2-fold increase in energies of activation with decreased transition temperature. The total phospholipid (TPL) and cholesterol (CHL) contents decreased significantly with lowering of diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), phosphatidylinositol (PI), and phosphatidylserine (PS), while lysophospholipid (lyso), sphingomyelin (SPM), and phosphatidylcholine components were found to be elevated. Brain mitochondrial membrane was somewhat more fluidized in epileptic animals. Possible consequences of mitochondrial respiratory chain (MRC) dysfunction are discussed. In conclusion, impairment of MRC function along with structural alterations suggests novel pathophysiological mechanisms important for chronic epileptic condition.
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PMID:Structural and functional alterations in mitochondrial membrane in picrotoxin-induced epileptic rat brain. 1569 21

Sucrose density gradient centrifugation of broken cell suspensions of autotrophically grown Euglena gracilis Klebs. has allowed the separation of chloroplasts, mitochondria, and peroxisomes. Chlorophyll was taken as a marker for chloroplasts, fumarase and succinate dehydrogenase for mitochondria, and glycolate oxidoreductase for peroxisomes. Peaks of malate dehydrogenase (l-malate-NAD oxidoreductase, EC 1.1.1.37) activity were found in the mitochondrial and peroxisomal fractions. Acrylamide gel electrophoresis showed specific isoenzymes in the mitochondrial and peroxisomal fractions and a third isoenzyme in the supernatant. The mitochondrial isoenzyme which had a Km (oxaloacetate) of 30mum was inhibited by oxaloacetate concentrations above 0.17 mm, an inhibition of 50% being given by 0.9 mm oxaloacetate. The peroxisomal isoenzyme had a Km (oxaloacetate) of 24 mum, was inhibited by oxaloacetate concentrations above 0.13 mm, 50% inhibition being given by 0.25 mm oxaloacetate. Malate dehydrogenase activity in the supernatant did not show inhibition by increasing oxaloacetate concentration, the Km (oxaloacetate) being 91 mum.In division synchronized cultures of Euglena, all three isoenzymes of malate dehydrogenase were synthesized over the light phase of the cycle. Darkening light phase cultures did not affect malate dehydrogenase activity. The addition to cultures of cycloheximide at a concentration previously shown to inhibit protein synthesis on Euglena cytoplasmic ribosomes completely inhibited increase in malate dehydrogenase activity over the cell cycle. Malate dehydrogenase activity was unaffected by the addition of chloramphenicol in amounts known to inhibit preferentially protein synthesis on 70S ribosomes.
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PMID:Malate dehydrogenase isoenzymes in division synchronized cultures of euglena. 1665 78


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