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)

Using histochemical procedures for the detection of lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), and cytochrome c oxidase (cytox), we investigated the levels of these enzymes of the energy metabolism in postimplantation rat embryos (9.5-12.5 days of gestation). On day 10.5 of gestation, the neural tube, somites, myocardium, and mesenchyme displayed moderate levels of LDH activity; this activity gradually increased in strength, so that, on day 12.5 of gestation, intense LDH activity was uniformly distributed in these intraembryonic tissues. In contrast to LDH, distinct regional differences in the distribution of SDH and cytox were detected. On day 10.5 of gestation, the myocardium exhibited weak to moderate SDH and cytox activity, and on day 11.5, the myocardial activity of these enzymes had become moderate to intense. However, in all other embryonic tissues, e.g., the neural tube and somites, only weak SDH and cytox activity was present. On day 12.5 of gestation, the myocardium displayed very intense SDH and cytox activity, whereas the mantle layer of the neural tube, the spinal ganglia, and the myotomes exhibited only moderate levels of SDH and cytox activity. In the matrix of the neural tube and mesenchyme, these enzyme activities remained at low levels. At electron microscopy, cytox activity was detectable in the spaces between the inner and outer membranes as well as in the intracristal spaces of mitochondria. In general, cytox activity increased in parallel with the differentiation of mitochondria (i.e., increased mitochondrial numbers and size, and the development of mitochondrial cristae), but when the distribution of the cytox activity was considered in detail, it was found to differ among mitochondria.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Histochemical studies of enzymes of the energy metabolism in postimplantation rat embryos. 283 38

There is a renewed interest in the structure and functioning of the mitochondrial respiratory chain with the realization that a number of genetic disorders result from defects in mitochondrial electron transfer. These socalled mitochondrial myopathies include diseases of muscle, heart, and brain. The respiratory chain can be fractionated into four large multipeptide complexes, an NADH ubiquinone reductase (complex I), succinate ubiquinone reductase (complex II), ubiquinol oxidoreductase (complex III), and cytochrome c oxidase (complex IV). Mitochondrial myopathies involving each of these complexes have been described. This review summarizes compositional and structural data on the respiratory chain proteins and describes the arrangement of these complexes in the mitochondrial inner membrane. This biochemical information is provided as a framework for the diagnosis and molecular characterization of mitochondrial diseases.
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PMID:Complexity and tissue specificity of the mitochondrial respiratory chain. 284 7

In a previous report, mitochondria were proposed as a subcellular structure where recognition sites for peripheral benzodiazepine ligands are located in adrenal glands. The present study examines the subcellular distribution of specific binding sites for PK 11195 in eight tissues and compares the relative densities of these binding sites in mitochondrial-enriched fractions with the relative activities of two mitochondrial marker enzymes. In all eight tissues examined, PK 11195 binding sites were found to subfractionate in a manner nearly identical to that of the mitochondrial enzyme succinate dehydrogenase. The subcellular distribution patterns of specific PK 11195 binding sites were unrelated to the distribution patterns of marker enzymes for plasma membranes, lysosomes, or endoplasmic reticulum. Scatchard analyses of mitochondrial fractions from all eight tissues demonstrated a greater than 100-fold difference in the densities of PK 11195 binding sites, the extremes being 140 and 1 pmol/mg of protein in adrenal and brain tissues, respectively. There was no correlation between the relative density of PK 11195 binding sites and the specific activities of succinate dehydrogenase and cytochrome c oxidase. These results suggest that the density of peripheral-type benzodiazepine receptors in mitochondria is tissue dependent and apparently regulated independently of the mechanisms by which these two mitochondrial enzymes are expressed or function. The photoaffinity probe PK 14105 was used to photolabel the peripheral-type benzodiazepine binding sites of mitochondrial fractions prepared from the eight tissues. In all preparations, a 17,000-Da polypeptide is specifically labeled as determined by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels. Thus, it appears that the protein recognition site for isoquinoline carboxamides of peripheral-type benzodiazepine receptor complexes is similar in all mitochondrial preparations.
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PMID:Molecular characterization and mitochondrial density of a recognition site for peripheral-type benzodiazepine ligands. 284 47

It has been proposed that the acquisition of efficient energy-transducing mitochondria after birth is mediated by an ATP-dependent mechanism "that causes the rapid maturation of mitochondria without requiring either transcription or translation" (Pollak, J. K., and Sutton, R. (1980) Trends Biochem. Sci. 5, 23-27). Investigation of developmental changes in rat liver mitochondria during the first 6 postnatal h showed that fetal mitochondria had low State 4, State 3, and uncoupled rates of respiration, inefficient coupling between respiration and phosphorylation, and low membrane potentials and proton electrochemical gradients under State 4 conditions. In contrast, hepatic mitochondria from 1-h-old neonates showed increased respiratory control and ADP/O ratios and adult proton electrochemical gradient and membrane potential values. In parallel with these changes, mitochondria became enriched in adenine nucleotides and underwent a 50% reduction in matrix volume. During the first postnatal hour, an increase in mitochondrial succinic dehydrogenase, cytochrome c oxidase, and F1-ATPase activities takes place in the neonatal liver concurrent with a preferential postnatal increase in the in vivo rates of protein synthesis for mitochondrial proteins. In particular, the amount of F1-ATPase increased from 109 +/- 9 to 206 +/- 5 ng/microgram of mitochondrial protein in the first hour of postnatal life. Inhibitors of cytosolic protein synthesis present during the first 2 h of life blocked the postnatal increase in respiratory control and ADP/O ratios, succinic dehydrogenase activity, and F1-ATPase content; but they had no effect on the increase in adenine nucleotide concentrations and mitochondrial volume contraction. This indicates that the acquisition of an efficient coupling between respiration and phosphorylation is dependent on de novo protein synthesis and cannot be brought about by the postnatal increase in adenine nucleotides. The increase of State 4 and uncoupled rates of respiration during the first 2 postnatal h was resistant to protein synthesis inhibitors. We suggest that the postnatal increase in these parameters is due to the reduction of mitochondrial volume occurring during that time, which, in turn, may be triggered by the concurrent enrichment in adenine nucleotides.
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PMID:Postnatal development of rat liver mitochondrial functions. The roles of protein synthesis and of adenine nucleotides. 289 64

Mitochondrial enzymes and respiration were studied in the hearts of mice exposed to ethanol in utero from gestational Day 8 to parturition. This treatment had previously been shown by electron microscopy to result in myofibril loss and mitochondrial abnormalities. Ethanol was administered to pregnant mice by a liquid diet paradigm and pair-fed dams were used as controls. Ethanol exposure in utero reduced the activities of two mitochondrial inner membrane enzymes, cytochrome c oxidase and succinate dehydrogenase, in the hearts of perinatal mice. Secondly, mitochondrial respiration under both State 3 and 4 conditions with a NAD-linked substrate was depressed in the hearts obtained from the ethanol-exposed fetal mice. However, when a flavin-linked substrate was used, State 3 (ADP-stimulated) but not State 4 respiration was depressed. This study illustrates that in utero exposure to ethanol is deleterious to the functioning of cardiac mitochondria in newborn mice, which in turn could contribute to the development of the heart pathologies present in the Fetal Alcohol Syndrome.
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PMID:Cardiac mitochondrial abnormalities in a mouse model of the fetal alcohol syndrome. 289 3

Keshan disease (KD) is a cardiomyopathy endemic in certain areas of China, characterized by severe deterioration and multiple focal necrosis. In the present paper we describe abnormalities of the structure and function of myocardial mitochondria from patients with subacute Keshan disease. Activities of succinate dehydrogenase, succinic oxidase, cytochrome c oxidase, H(+)-ATPase and its sensitivity to oligomycin and the response of membrane potential to energization by ATP were significantly decreased. However, the spectrum of reduced-minus-oxidized cytochromes in patients' mitochondria showed no obvious difference in the content of cytochrome c oxidase (aa3). There was also a marked decrease in lipid fluidity of affected mitochondria, and an abnormal amount of moderately electron dense amorphous inclusions. Electron-microscopic x-ray microanalysis and exposure to protein digestion reagent demonstrated that these inclusions are not Ca3(PO4)2, but are, probably, proteinaceous in nature. Affected mitochondria had markedly decreased selenium content. The defects in myocardial mitochondria from patients with chronic Keshan disease were less extensive than those in patients with subacute Keshan disease. We propose that Keshan disease be classified as a form of "mitochondrial cardiomyopathy".
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PMID:Keshan disease--an endemic mitochondrial cardiomyopathy in China. 290 94

In vivo administration of L-thyroxine (L-T4) in Anabas testudineus, while significantly stimulated the activities of cytochrome c oxidase and alpha-glycerophosphate dehydrogenase (alpha-GPDH), inhibited glucose-6-phosphate dehydrogenase (G-6-PDH), cytosolic and mitochondrial malate dehydrogenase (cyt. MDH; mit. MDH), and Mg2+ DNP-dependent adenosine triphosphatase (Mg2+ ATPase) activities. The activities of lactate dehydrogenase (LDH), succinate dehydrogenase (SDH), and catalase remained unaltered after L-T4 treatment. Administration of protein synthesis inhibitors such as actinomycin D, while significantly inhibited cytochrome oxidase, alpha-GPDH, catalase, SDH, and Mg2+ ATPase activities, did not change LDH, cyt. MDH, and mit. MDH activities. Chloramphenicol injection significantly stimulated cytochrome oxidase, alpha-GPDH, and G-6-PDH activities. Simultaneous injections of actinomycin D or chloramphenicol with 3,5,3'-triiodo-L-thyronine (L-T3) or L-T4 prevented the effects of thyroid hormones on enzyme activities, when compared to the respective controls.
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PMID:Oxidative metabolism in a teleost, Anabas testudineus Bloch: effect of thyroid hormones on hepatic enzyme activities. 292 Sep 3

High HCO3(-)-ATPase activity is known to exist in mitochondria of renal tubular cells. In brush border membrane (BBM) preparations of proximal tubules such an anion-stimulated enzyme was also found. However, these preparations always contained mitochondrial markers. The putative localization and the role of this ATPase in BBM is still controversial. Some authors consider the HCO3(-)-ATPase in the BBM to be a mitochondrial contamination; others attribute to this ATPase a key role in H+ transport in the proximal tubule. To reinvestigate this problem, BBMs from rat kidney cortex were isolated by a simple, rapid (1.5-h) Ca2+-precipitation method, yielding a BBM fraction enriched 12.4-fold with respect to the marker enzyme leucine aminopeptidase (LAP). There was no basolateral Na+-K+-ATPase and no mitochondrial succinate dehydrogenase detectable. Cytochrome c oxidase was drastically reduced to 7 +/- 1% of that observed in the homogenate (TH). The activity of HCO3(-)-ATPase in the BBM fraction was 19 +/- 4 IU/g protein, i.e., 27% that of the homogenate. As sonication of the TH exclusively increases the activity of HCO3(-)-ATPase, its relative activity was 7.5% and thus equal to that of the mitochondrial marker. In many BBM preparations no HCO3(-)-ATPase was detectable. In those BBM preparations in which traces of HCO3(-)-ATPase were found, this activity coincided with that of cytochrome c oxidase in the respective preparation. There was a constant activity ratio of cytochrome c oxidase/HCO3(-)-ATPase in the TH, BBM, and pellet 1. The activity of HCO3(-)-ATPase in BBM did not depend on the activity of LAP.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evidence for mitochondrial origin of the HCO3(-)-ATPase in brush border membranes of rat proximal tubules. 298 70

The main purpose of the present study was to test the hypothesis that adrenergic stimulation of muscle fibres during exercise is a major stimulus for the training-induced enhancement of skeletal muscle respiratory capacity. Therefore, Sprague-Dawley rats either underwent bilateral surgical ablation of the adrenal medulla or were sham-operated. Furthermore, unilateral surgical extirpation of the lumbar sympathetic chain was performed. Half of the rats were then trained for 12 weeks by swimming (up to 5.5 h X day-1, 4 days X week-1) and the remaining rats were sedentary controls. In the gastrocnemius muscle, training significantly increased the mitochondrial enzymes citrate synthase, succinate dehydrogenase, cytochrome c oxidase, and 3-hydroxyacyl-CoA dehydrogenase. In sham-operated rats, the increases were 40%, 43%, 66%, and 25%, respectively, in legs with intact sympathetic innervation. The training-induced enzyme adaptation after adrenodemedullation and/or sympathectomy was not significantly lower than these control values. In sham-operated rats, training decreased resting plasma insulin and glucagon levels and increased liver glycogen content. Similar changes were induced by adrenodemedullation, but training did not augment these changes in adrenodemedullated rats. In conclusion, the data suggest that neither adrenomedullary hormones nor local sympathetic nerves are prerequisites for the training-induced increase in muscle mitochondrial enzymes. The training-induced decline in resting plasma insulin and glucagon levels in intact rats may be mediated by adrenomedullary hormones.
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PMID:Skeletal muscle and hormonal adaptation to physical training in the rat: role of the sympatho-adrenal system. 298 95

Protein-lipid complexes in organic solvents can be used as the starting material in the reassembly of functional planar and spherical bilayers (Montal, M., Darszon, A. and Schindler, H. (1981) Q. Rev. Biophys. 14, 1-79). The transfer of three enzymes of the inner mitochondrial membrane into organic solvents as protein-lipid complexes has been studied to understand better the extraction process. The enzymes studied were cytochrome c oxidase, ATPase and succinate dehydrogenase. These enzymes were transferred into hexane and diethyl ether in an active state, however, the activities extracted varied quantitatively, depending on the amount of protein of the starting preparation, the concentration of phospholipids and the cation employed. In all conditions cytochrome c oxidase was extracted with the highest yield and specific activity, and it was actually enriched in the organic extract. The values for succinate dehydrogenase and ATPase were lower, but their specific activities were similar to those of the starting material. This indicates that some membrane proteins are preferentially extracted into organic solvents in a functional state. The enzymes, as protein-lipid complexes, are fairly stable in organic solvents; in a month of storage at 4 degrees C in hexane some enzymes loose less than 50% of their activity.
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PMID:Extraction of mitochondrial membrane proteins into organic solvents in a functional state. 299 58


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