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)

Spheroplasts that were osmotically stable in 0.2M Tris-HCl--0.02M EDTA were prepared from the autotrophically grown cells of Pseudomonas thermophila K-2. The spheroplasts possessed 90--95% of the hydrogenase activity of the whole cells. The half-life time of hydrogenase in the spheroplasts at 80 degrees C was 8.5 min. A spectrophotometric technique was developed for determining the membrane-bound hydrogenase in the presence of sulfhydryl compounds with methylene blue as electron acceptor. The maximal specific activity of hydrogenase in extracts prepared in the anaerobic conditions in the presence of dithiothreitol and Mg2+ and Mn2+ ions was 10 +/- 3 units per 1 mg of protein, which closely corresponded with the activity of hydrogenase in the whole cells. Almost all activity of hydrogenase assayed with methylene blue was localized in the membrane fraction. The activity of soluble NAD-specific hydrogenase was not detected. Large particles located in 60-70% sucrose had the highest hydrogenase activity upon fractionation in a continuous sucrose concentration gradient. The second, lower peak of the hydrogenase activity was detected in fractions of 40--50% sucrose. As was found by electron microscopy, the size of membrane vesicles with the hydrogenase activity varied within the range of 68--156 nm. The membrane preparations possessed the activity of NADH-dehydrogenase, NADH-oxidase and succinate dehydrogenase as well.
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PMID:[Localization of hydrogenase in the cells of the thermophilic hydrogen bacterium, Pseudomonas thermophila]. 21 85

Bacteriochlorophyll a reaction-center complex I from Chlorobium limicola f. thiosulfatophilum 6230 (Tassajara) was incubated in 2 M guanidine - HCl and then chromatographed on cross-linked dextran or agarose gel. Two principal components were separated: a larger component with photochemical activity (bacteriochlorophyll a reaction-center complex II) and a smaller component without activity (bacteriochlorophyll a protein). Complex II contains carotenoid, bacteriochlorophyll a, reaction center(s), and cytochromes b and c, but lacks the well characterized bacteriochlorophyll a protein contained in Complex I. Complex II carries out a light-induced reduction of cytochrome b along with an oxidation of cytochrome c.
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PMID:An enriched reaction center preparation from green photosynthetic bacteria. 99 Feb 92

The involvement of a histidine residue of the membrane-anchoring protein (QPs) fraction in reconstitution of succinate dehydrogenase to form succinate-ubiquinone reductase is studied by using a histidine-modifying reagent, diethylpyrocarbonate (DEPC). A maximum inactivation of 80% of reconstitutive activity is obtained when QPs is treated with 1 mM DEPC at 0 degrees C for 30 min in 50 mM Tris-HCl (pH 7.0). DEPC also inactivates about 85% of intact succinate-ubiquinone reductase. The inactivation of succinate-ubiquinone reductase by DEPC is a result of the modification of essential histidine residues of succinate dehydrogenase. The inactivation is not a result of the modification of the histidine residue in QPs which is essential for interaction with succinate dehydrogenase because the QPs dissociated from the inactivated succinate-ubiquinone reductase is active in reconstitution with active succinate-dehydrogenase. Apparently, the essential histidine in QPs is shielded by succinate dehydrogenase and thus inaccessible to DEPC modification in succinate-ubiquinone reductase. The involvement of a histidine residue of QPs in interaction with succinate dehydrogenase is further evident by the presence of 553 nm shoulder on the alpha-absorption peak of reduced cytochrome b-560 (a characteristic of physical association of QPs with succinate dehydrogenase) in the DEPC-inactivated succinate-ubiquinone reductase. This shoulder disappears from a mixture of succinate dehydrogenase and DEPC-treated QPs when reduced with dithionite. About one histidine residue per molecule of QPs is modified in the DEPC-treated sample, suggesting that only one histidine residue is essential for interaction with succinate dehydrogenase. This essential histidine group is located in the smaller subunit (Mr 13,000) of QPs.
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PMID:Involvement of a histidine residue in the interaction between membrane-anchoring protein (QPs) and succinate dehydrogenase in mitochondrial succinate-ubiquinone reductase. 199 11

The effect of lidocaine-HCl on muscle spindles in the masseter muscle of developing mice was investigated. Repeated injections of mice with anesthetic in the short term decreased the diameters of primary endings, intrafusal muscle fibers and outer capsules in the equatorial regions of muscle spindles, and caused a drop in the succinic dehydrogenase activity in intrafusal muscle fibers of the muscle spindles. In addition, the diameters did not recover to the control value even after about 10 weeks following cessation of anesthetic treatment. Thus, the present results suggest that repeated use of lidocaine-HCl in developing animals may cause dysfunction of the skeletal muscles.
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PMID:Prolonged degeneration of muscle spindles in the masseter muscle after treatment of developing mice with the local anesthetic lidocaine hydrochloride. 252 35

The possible role of Mg2+-HCO3-ATPase, carbonic anhydrase and several other enzymes in rat intestinal mucosa as mediators of the action of aldosterone has been examined. The small-intestinal tract was cut into seven segments, 15 cm each in length and the mucosa was scraped off, homogenized in 50 mM D-mannitol-2 mM Tris-HCl buffer (pH 7.1), differentially fractionated and a crude brush border was obtained. The mucosa from the colon and rectum was combined and used as the large-intestinal sample. Five days after the adrenalectomy, activities of brush border Mg2+-HCO3-ATPase and supernatant carbonic anhydrase from the upper small intestine decreased to about 60 and 40% of normal values, respectively. Activities of Na+-K+-ATPase, beta-glycerophosphatase and succinate dehydrogenase were all decreased. Two and 4 h after i.p. injection of aldosterone (40 micrograms/kg) to adrenalectomized rats, all enzyme activities increased except for Na+-K+-ATPase in the upper small intestine. In contrast, Mg2+-HCO-3-ATPase and carbonic anhydrase activities were unchanged 3 h after i.p. injection of dexamethasone (200 micrograms and 1 mg/kg). The activation of both Mg2+-HCO3-ATPase and carbonic anhydrase by a single injection of aldosterone was blocked by pretreatment with cycloheximide (1 mg/kg). These results suggest that aldosterone may induce the synthesis of enzyme proteins in the intestinal mucosa.
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PMID:Brush border Mg2+-HCO-3-ATPase, supernatant carbonic anhydrase and other enzyme activities isolated from rat intestinal mucosa: effect of adrenalectomy and aldosterone administration. 613 8

Through a methodological evaluation, reliable histochemical and biochemical methods for succinate dehydrogenase activity in cultured human skin fibroblasts and amniotic fluid cells were developed. The histochemical method includes a cleaning of the cultured cells in 1 mM malonate in 0.9% NaCl, air-drying and fixation in acetone (5 min at -20 degrees C), coating of cells with CoQ10 (0.2 mg/ml in ether/acetone) and incubation for 1 h at 37 degrees C in 50 mM succinate and 0.5 mg/ml Nitro BT in 200 mM phosphate buffer, pH 7.6 PMS as an intermediate electron carrier was found inferior to exogenous CoQ10. Both types of cells exhibit equal activity. In the biochemical method homogenizing was performed in 50 mM Tris-HCl buffer, pH 7.5, and 200 mM sucrose. The standard incubation was 2.0 mM INT and 10 mM succinate in 10 mM Tris-HCl buffer, pH 7.5 for 1 h at 37 degrees C. The apparent Km values for INT and succinate were estimated to 0.39 mM and 0.13 mM, respectively, while I0.5 for malonate was 0.46 mM. Activity in amniotic fluid cells was 18.1 pkat/mg protein and in human skin fibroblasts 20.3 pkat/mg protein. Specificity of the methods was tested by use of a Chinese hamster fibroblast strain B9 known to be succinate dehydrogenase deficient in addition to various control experiments. Congruent results were obtained with the two methods.
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PMID:Succinate dehydrogenase activity in cultured human skin fibroblasts and amniotic fluid cells. A methodological study. 687 23

A decrease in MAO by gastrin stimulation was observed in 13 of 20 hyperthyroid patients. Five of these 13 cases had achlorhydria. The decrease in gastric acid secretion had no relation to the duration of symptoms, serum T3 and T4 levels, serum antithyroglobulin antibody levels and serum antithyroid microsomal antibody levels. Gastroscopy with biopsy was performed in 17 cases. In patients with achlorhydria, macroscopic and histological atrophy was not observed in the body, and parietal cells were present and their succinic dehydrogenase activity was normal. Electron microscopy of the parietal cells of patients with achlorhydria showed that their cells were similar to those in the resting state of healthy subjects with the ability to secrete normal amounts of gastric acid. These findings demonstrate that the decrease in gastric acid secretion in hyperthyroidism is not caused by any structural changes in the gastric mucosa but by functional suppression. In the present experiment, this suppression was found resistant to gastrin. A rise in serum gastrin level was observed in 8 cases. Either achlorhydria or marked hypoacidity was found in 6 cases with the level more than 400 pg/ml. The HCl administration temporarily lowered elevated gastrin levels, and feedback inhibition by HCl was found to be maintained. A rise in gastric pH was considered to be one of the prerequisites for an increase in serum gastrin level.
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PMID:Gastric acid secretion, serum gastrin and parietal cell histology in hyperthyroidism. 707 32

Experimental hyperthyroidism was produced in rats by thyroxin injection, and changes in gastric acid secretion and serum gastrin level were determined to analyze the relation between these changes and hyperthyroidism. Administration of thyroxin to two groups of rats-20 micrograms per 100 g of body weight for 20 days and 75 micrograms for 7 days-brought about significant increases in serum T3 level, gastric pH and serum gastrin level. An increase in gastric pH took place later than that in serum T3 level; this time lag implies that a decrease in acid secretion was not caused by an direct effect of thyroxin on the parietal cell but by its secondary effect. In the T4-injected rats with decreased gastric acid secretion, the parietal cell remained normal in form and succinic dehydrogenase activity was also normal. The electron microscopical observations showed nothing abnormal in the parietal cells. These findings suggest that a decrease in acid secretion was not due to any structural changes in the gastric mucosa but to functional suppression. The serum gastrin level rose in correlation with an increase in gastric pH and fell by HCl administration to the stomach. Feedback inhibition by pH remained in the G cell.
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PMID:Gastric acid secretion, serum gastrin and parietal cell histology in rat hyperthyroidism. 707 33

Controversial data have been obtained with direct cellular protection by prostaglandins and sulfhydryls. In the present studies, we compared the merits and liabilities of currently available cell viability assays, some of which have not been previously employed in studies of the gastric mucosa. We also tested the hypothesis that length of incubation of isolated cells with protective agents might influence the degree of cellular damage. Gastric mucosal cells were isolated from nonfasted rats and digested with various concentrations of pronase and/or EGTA. Cell viability was assessed by trypan blue and fast green exclusion, fluorescein diacetate hydrolysis, chromium release, LDH release, mitochondrial succinate dehydrogenase activity and nuclear fluorescence induced by ethidium bromide. The experiments revealed that both pronase and EGTA are needed to obtain mucosal cells with optimal yield and initial viability and that sequential additions of pronase (30 min) and EGTA (30 min), rather than their combination (60 min), increased viability without decreasing yield. Cell viability and yield were better when pronase was used in the first incubation. For LD50 determinations, a cell suspension was incubated with ethanol (0%-15%) for 5 min. For studying the effects of protective agents, the cells were pretreated with 16,16-dmPGE2 or cysteamine HCl at 37 degrees C for 30 min before a 5-min exposure to 7.5% or 15% ethanol. The LD50 value for ethanol injury was approximately 15% for all assays except LDH, where the LD50 value was 8.5%. Preincubating gastric mucosal cells for 30 min with 16,16-dmPGE2 or cysteamine resulted in no preservation of cell viability. However, when cells were preincubated with one of the protective agents for 60 min and then exposed to 8% or 10% ethanol for 5 min, partial protection was observed when assessed by succinate dehydrogenase activity and, in certain cases, by LDH release. We conclude that all seven cell viability assays yield a measurable LD50 value for ethanol-induced cell injury, but the results may vary by as much as 82%. Low concentrations of both pronase and EGTA are needed to obtain isolated mucosal cells with both high yield and initial viability. Biochemical measures of mitochondrial activity and nuclear damage provide reliable evidence of cell viability and should be used to complement membrane permeability assays. Long preincubation of cells (60 min) with protective agents resulted in only slight protection of mitochondrial function, in contrast to the rapid induction of gastroprotection seen with these compounds in vivo. We therefore surmise that processes that contribute to organ protection occur faster and more efficiently than those that control direct cell injury and protection.
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PMID:Isolated rat gastric mucosal cells: optimal conditions for cell harvesting, measures of viability and direct cytoprotection. 878 50

Efforts have been made to reduce the undesirable side effects of cisplatin, mainly nephro- and neurotoxicity, but their reduction is usually accompanied by a concomitant inhibition of antitumor activity. The local anesthetic procaine hydrochloride (P.HCl) improves the therapeutic index of cisplatin not only by the reduction of its nephro- and hemotoxicity, but also by an increase of its antitumor activity. We therefore investigated the effects of a combined treatment of cisplatin and P.HCl on rat kidneys and compared this to kidneys from rats treated with a toxic dose of cisplatin or P.HCl alone. Treatment with a saline solution was used as control. Dehydrogenase activities [succinate dehydrogenase (SDH) and NADPH diaphorase reaction demonstrating nitric oxide synthase (NOS/NADPHd)] and phosphatase activities [K -nitrophenyl phosphatase (K pNPPase), alkaline phosphatase (AlPase) and acid phosphatase (AcPase)] were studied on cryostatic sections of kidneys from controls and treated rats. Evidence of heavy morphological damage and altered AlPase and AcPase activities induced by cisplatin were observed in the S3 segment of the proximal tubules. In addition, SDH and K pNPPase activities showed some changes in the distal tubule cells. The NOS/NADPHd activity in macula densa was drastically reduced. Combined treatment of cisplatin and P.HCl greatly attenuated morphological alterations of the rat kidney and reduced the changes in enzyme activities, except for NOS/NADPHd activity, compared to the cisplatin-treated group of animals. The study indicates that, in cisplatin-induced nephrotoxicity, a significant role is played by enzyme activities, in particular K pNPPase and NOS/NADPHd, and that P.HCl can mitigate the nephrotoxicity of cisplatin, possibly by influencing some enzyme activities involved in important renal metabolic pathways.
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PMID:Protective effect of procaine hydrochloride on cisplatin-induced alterations in rat kidney. 1243 38


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