Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.3.5.1 (succinate dehydrogenase)
 8,177 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Surgical cardiac denervation was carried out in dogs under halothane anaesthesia. In a paired experimental design control biopsy specimens were obtained before surgical denervation. The dogs were allowed to recover and three weeks to elapse before the second biopsy specimen was taken. Both right and left ventricular specimens had higher in vitro oxygen consumption after denervation than before. Other specimens were immediately cooled in hexane at -60 degrees C and stored under liquid nitrogen until analysed. Succinate dehydrogenase and cytochrome oxidase activities were then measured histochemically in sequential 10 or 12 microns sections. There was no significant difference between the enzyme activities measured before or after cardiac denervation (succinate dehydrogenase 20.3(6.3) before, 19.4(4.02) pmol.H2.cm-2.s-1, after; cytochrome oxidase 223(73.4) before, 263(61.6) (measured as extinction coefficient) after). Thus the changes in oxygen consumption in the chronically denervated dog heart are not due to any lack of these mitochondrial enzymes.
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PMID:Effect of lack of noradrenaline on myocardial oxygen consumption in denervated dog hearts. 282 57

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

The antigen reacting with complement-fixing antibodies in the sera of patients with primary biliary cirrhosis was localized predominantly in the mitochondrial fraction of tissue homogenates obtained by differential centrifugation. Purified mitochondrial preparations had a high content of the antigen whereas purified lysosomes failed to fix complement with PBC sera. Analysis of a number of fractionation experiments showed a high correlation between antigen content and the mitochondrial enzyme succinic dehydrogenase in all fractions. There was much poorer correlation with lysosomal and micrososomal enzyme markers. The patterns of staining obtained with a fluorescein conjugate of IgG from a PBC patient closely paralleled those obtained with a histochemical method for the demonstration of succinic dehydrogenase, further confirming the mitochondrial localization of the antigen. Staining was brightest in cells containing mitochondria with well-developed cristae. Studies on mitochondria fragmented by osmotic lysis, hexane, lysolecithin, and ultrasound suggest that the antigen is associated with the mitochondrial inner membranes.
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PMID:Mitochondrial antibodies in primary biliary cirrhosis. I. Localization of the antigen to mitochondrial membranes. 416 42

The effect of n-hexane, 2-hexanol, 5-hydroxy-2-hexanone, 2,5-hexanediol, methyl n-butyl ketone ( MnBK ) and 2,5-hexanedione (2,5-HD) has been studied in vitro on crystalline glyceraldehyde-3-phosphate dehydrogenase (GAPDH), DL-glyceraldehyde-3-phosphate: NAD oxidoreductase (phosphorylating) EC. 1.2.1.12 and phosphofructokinase (PFK) ATP: D-fructose-6-phosphate-1-phosphotransferase; EC. 2.7.1.11 and lactic dehydrogenase (LDH) L-lactate: NAD+ oxidoreductase, EC. 1.1.1.27. MnBK and 2,5-HD both inhibited GAPDH and PFK activities selectively. n-Hexane and 2-hexanol had no effect on GAPDH and PFK activities; 5-hydroxy-2-hexanone and 2,5-hexanediol exhibited a slight inhibitory effect on these enzymes. Neither metabolites of n-hexane have any effect on LDH activity. 2,5-Hexanedione did not inhibit transketolase (D-sedoheptulose-7-phosphate: D-glyceraldehyde-3-phosphate glycolaldehyde transferase, EC. 2.2.1.1) and succinate dehydrogenase (succinate: 2,6-dichlorophenol-indophenol oxidoreductase, EC. 1.3.99.1) activities. The levels of ATP were reduced in 2,5-HD-treated cat sciatic nerves and returned to normal levels by exposing the nerve to sodium pyruvate.
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PMID:In vitro effect of n-hexane and its metabolites on selected enzymes in glycolysis, pentose phosphate pathway and citric acid cycle. 623 75

The in vitro cytotoxicity of urethane dimethacrylate composites cured at different times by visible light and after different aging times and extraction treatments was evaluated using succinic dehydrogenase activity in the mitochondria of a fibroblastic cell line to reflect cell viability. In addition, extractable chemicals associated with cell response were identified. The composite samples were tested untreated, polished, or extracted with water or 75% ethanol-water. Balb/c 3T3 fibroblasts were used as the cell culture system while MTT-formazan production was used as the toxicity parameter. Cell viability was calculated as a percentage of Teflon controls. Identification of the chemicals was measured by extracting the composites with 75% ethanol-water, separating the extract by HPLC, and identifying the fractions with mass spectroscopy. In general, cell viability increased continuously with curing time for differently treated samples at high aging times (288 h) while it decreased when the composites were not aged (0 h). In addition, for 75% ethanol or water-extracted composites, cell viability increased within the first 24 h of aging and reached a plateau after 72 h. Lowest cytotoxicity occurred when the samples were extracted with the 75% ethanol solution. The highest cytotoxic effects were found when the samples were untreated. Slightly reduced cytotoxic effects were seen with polished composites. The results suggest that curing the light-activated composites for a minimum of 150 s and post-curing for 24 h is required to attain comparable biocompatibility with the Teflon control. Removing the oxygen-inhibited layer from these composites decreased the cytotoxicity by 33% while extracting the composites with 75% ethanol-water decreased it by 77%. Chemicals released from the surface accounted for approximately 40% of cellular response while about 60% of the response was due to chemical components released from the bulk. The primary leachable component from the composites was UDMA monomer. Small quantities of 1,6 hexane diol methacrylate, camphoroquinone, and 2,4,6-tritertiarybutyl phenol also were found.
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PMID:Cytotoxicity of urethane dimethacrylate composites before and after aging and leaching. 945 55

Electronic energy transfer processes in chlorosomes isolated from the green sulphur bacterium Chlorobium tepidum and from the green filamentous bacterium Chloroflexus aurantiacus have been investigated. Steady-state fluorescence excitation spectra and time-resolved triplet-minus-singlet (TmS) spectra, recorded at ambient temperature and under non-reducing or reducing conditions, are reported. The carotenoid (Car) pigments in both species transfer their singlet excitation to bacteriochlorophyll c (BChlc) with an efficiency which is high (between 0.5 and 0.8) but smaller than unity; BChlc and bacteriochlorophyll a (BChla) transfer their triplet excitation to the Car's with nearly 100% efficiency. The lifetime of the Car triplet states is approximately 3 micros, appreciably shorter than that of the Car triplets in the light-harvesting complex II (LHCII) in green plants and in other antenna systems. In both types of chlorosomes the yield of BChlc triplets (as judged from the yield of the Car triplets) remains insensitive to the redox conditions. In notable contrast the yield of BChlc singlet emission falls, upon a change from reducing to non-reducing conditions, by factors of 4 and 35 in Cfx. aurantiacus and Cb. tepidum, respectively. It is possible to account for these observations if one postulates that the bulk of the BChlc triplets originate either from a large BChlc pool which is essentially non-fluorescent and non-responsive to changes in the redox conditions, or as a result of a process which quenches BChlc singlet excitation and becomes more efficient under non-reducing conditions. In chlorosomes from Cfx. aurantiacus whose Car content is lowered, by hexane extraction, to 10% of the original value, nearly one-third of the photogenerated BChlc triplets still end up on the residual Car pigments, which is taken as evidence of BChlc-to-BChlc migration of triplet excitation; the BChlc triplets which escape rapid static quenching contribute a depletion signal at the long-wavelength edge of the Qy absorption band, indicating the existence of at least two pools of BChlc.
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PMID:Electronic energy transfer involving carotenoid pigments in chlorosomes of two green bacteria: Chlorobium tepidum and Cholroflexus aurantiacus. 1098 92

This was a study on the oxidative stress due to ischaemia (I) and reperfusion (R) in skeletal muscle tissue. Using a tourniquet, groups of rats were submitted to ischaemia for 4 h, followed by different reperfusion periods. The animals were divided in four groups: control; 4 h of ischaemia (IR); 4 h of ischaemia plus 1 h reperfusion (IR-1 h); 4 h of ischaemia plus 24 h reperfusion (IR-24 h); and 4 h of ischaemia plus 72 h reperfusion (IR-72 h). At the end of the procedures, samples of soleus muscle were collected and frozen in n-hexane at -70 degrees C. Cryostat sections were submitted to haematoxylin-eosin, succinate dehydrogenase (SDH) and nicotinamide adenine dinucleotide-tetrazolium reductase (NADH-TR) stains. An additional muscle sample was processed for electron microscopy. No alterations were found in control animals. IR group showed fibres had normal aspect besides some round, acidophilic and hypertrophic fibres. There were several fibres with angular outlines and smaller diameters in this group compared with control group. NADH-TR/SDH reaction was moderately intense in most fibres. In some fibres, cytoplasm showed areas without activity and other fibres had very intense reactivity. IR-1 h group showed oedema hypercontracted fibres with disorganized myofibrils, mitochondria with focal lesions and dilated sarcoplasmic reticulum. NADH-TR/SDH reaction was moderate to weak. IR-24 h showed intense inflammatory infiltrate in the endomysium and perimysium. NADH-TR/SDH reaction was similar to IR-1 h. IR-72 h showed necrotic fibres, areas with inflammatory infiltrate, reduced muscle fibres at different stages of necrosis and phagocytosis, and many small round and basophilic fibres characterizing a regeneration process. NADH-TR/SDH reaction was weak to negative. Our results suggest that ischaemia and the subsequent 1-, 24- and 72-h reperfusions induced progressive histological damage. Although progressive, it may be reversible because there were ultrastructural signs of recovery after 72-h reperfusion. This recovery could in part be due to the low oxidative stress identified by the morphological and histochemical analysis.
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PMID:Ischaemia and reperfusion effects on skeletal muscle tissue: morphological and histochemical studies. 1750 44