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)

Monocrotaline, a pyrrolizidine alkaloid, caused changes in most of the biochemical parameters in rats 12 days after a single dose of 120 mg/kg. These included significantly increased activities of hepatic succinate dehydrogenase, acid ribonuclease, acid phosphatase, gammaglutamyl transpeptidase and 5'-nucleotidase and decreased in the activities of glucose-6-phosphatase and cytochrome P450. The levels of DNA, RNA and glycogen in liver and albumin and protein in serum decreased while serum bilirubin increased. The histopathological changes in liver were characterized by diffused hepatocyte alterations in the form of ballooning, granular cytoplasm, indistinct cell outlines, nuclear changes, focal necrosis, and vascular damage. When picroliv, a standardized iridoid glycoside fraction of Picrorhiza kurroa, was administered orally in a dose of 25 mg/kg simultaneously with monocrotaline, alterations in most of the biochemical parameters along with the histopathological changes in liver caused by monocrotaline were prevented.
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PMID:Picroliv protects against monocrotaline-induced hepatic damage in rats. 190 81

Thioacetamide (100 mg/kg), when administered to normal rats, caused a significant increase in the activities of 5'-nucleotidase and gamma-glutamyl transpeptidase and a decrease in the activities of glucose 6-phosphatase and succinate dehydrogenase enzymes in the liver. DNA, RNA, and proteins were increased while the cytochrome P450 in the microsomal fraction and the glycogen content in the liver were decreased significantly. Elevations in the activities of GOT, GPT, and alkaline phosphatase and bilirubin content in serum were also observed. Picroliv, a standardised glycoside fraction of Picrorhiza kurroa, in doses of 12.5 and 25 mg/kg prevented most of the biochemical changes induced by thioacetamide in liver and serum. The hepatoprotective activity of Picroliv was comparable with that of silymarin, a known hepatoprotective agent obtained from seeds of Silybum marianum.
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PMID:Picroliv affords protection against thioacetamide-induced hepatic damage in rats. 206 53

The plasma membrane fraction of chicken osteoclasts was purified utilizing 20% continuous Percoll gradients. Biochemical marker enzyme analysis (ouabain-sensitive Na+,K(+)-ATPase and 5'-nucleotidase) indicated that plasma membrane enrichment was 11.87-fold and 7.25-fold, respectively, and contamination with mitochondria, endoplasmic reticulum, and lysosomes was low as determined by succinic dehydrogenase, NADH dehydrogenase, and N-acetylglucosaminidase activities, respectively. SDS latency of Na+,K(+)-ATPase and 5'-nucleotidase activities of the isolated plasma membranes revealed that 43-50% of vesicles were sealed, with 10-16% in the inside-out orientation, depending on the membrane fraction used. Electron microscopy confirmed the vesicular nature of the plasma membrane fraction. The plasma membrane Ca2(+)-ATPase had a high-affinity (KCa = 0.22 microM; Vmax = 0.16 mumol/mg per min) and a low-affinity (KCa = 148 microM; Vmax = 0.37 mumol/mg per min) component. Calmodulin (0.12 microM) had no effect on Ca2(+)-ATPase activity. However, trifluoperazine (0.1 mM), a calmodulin antagonist, strongly inhibited especially the high-affinity component of the enzyme. Vanadate and lanthanum also caused inhibition. In the presence of CDTA, a potent Ca2+ and Mg2+ chelating agent, high-affinity Ca2(+)-ATPase activity was abolished, indicating that trace Mg2+ was essential for activity. The Ca2(+)-ATPase substrate curve using ATP showed a high-affinity (Km = 12.3 microM; Vmax = 0.022 mumol/mg per min) and a low-affinity (Km = 43.8 microM; Vmax = 0.278 mumol/mg per min) component. These results demonstrate that osteoclasts have a plasma membrane Ca2(+)-ATPase with characteristics similar to the enzyme responsible for active calcium extrusion in other cells.
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PMID:Characterization of a Ca2(+)-ATPase in osteoclast plasma membrane. 214 47

A (H+ + K+)-ATPase-enriched membrane fraction derived from the fundic portion of hog gastric mucosa was obtained by a combination of differential and repeated 7% Ficoll gradient centrifugation. The microsomal membrane fraction isolated by repeated 7% Ficoll gradient centrifugation was free of ouabain-sensitive (Na+ + K+)-ATPase, 5'-nucleotidase and succinate dehydrogenase; and it was highly enriched in (H+ + K+)-ATPase and K(+)-stimulated p-nitrophenylphosphatase (p-NPPase). The (H+ + K+)-ATPase had a pH optimum of 7.4 and was stimulated by Tl+, K+, Rb+ and NH4+ with Ka values of 0.0667, 0.526, 0.667 and 3.03 mM, respectively, at this pH. On the other hand, monovalent cations such as Na+, Li+ and (CH3)4N+ as well as divalent cations such as Cu2+, Ca2+, Ba2+, Sr2+ and Cd2+ inhibited this enzyme activity concentration-dependently. Ouabain and oligomycin had no effect, whereas omeprazole, a specific (H+ + K+)-ATPase inhibitor, inhibited this enzyme activity in a pH-dependent manner. Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis showed a major band (greater than or equal to 90% of protein) at 97,400 daltons, which was phosphorylated in the presence of Mg2+ and [gamma-32P]-ATP and dephosphorylated in the presence of K+. The present method was very simple, and the (H+ + K+)-ATPase activity of the microsomal fraction obtained by this method was much higher compared with those obtained by other methods such as free-flow electrophoresis.
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PMID:Purification and characterization of (H+ + K+)-ATPase from hog gastric mucosa. 215 97

Merocyanine 540 (MC 540) is a photosensitizing dye that is used clinically for the purging of autologous bone marrow grafts and preclinically for the inactivation of enveloped viruses in blood products. Its mechanism of action is not yet well understood. This paper investigates the sites of MC 540-mediated photodamages in L1210 leukemia cells by examining the effects of MC 540-sensitized photoirradiation on several soluble and membrane-bound marker enzymes. When exposed to MC 540 and white light under a standard set of conditions, the activities of Na+/K(+)-ATPase, Mg2(+)-ATPase, and 5'-nucleotidase (three plasma membrane-bound enzymes) were reduced by 54, 49, and 55%, respectively. None of the intracellular enzymes included in this survey was affected by MC 540-sensitized photoirradiation as long as the plasma membrane remained intact. The two soluble enzymes, lactate dehydrogenase and malate dehydrogenase, remained refractory to MC 540-sensitized photoirradiation even after the plasma membrane had been disrupted. By contrast, the activities of the membrane-bound enzymes, NADPH-cytochrome c reductase and succinate dehydrogenase, were reduced in cell lysates by 55 and 81%, respectively. Purified NADPH-cytochrome c reductase was about 3 times less sensitive than the microsomal enzyme, suggesting that the membrane environment facilitated photoinactivation. The MC 540-sensitized photoinactivation of enzymes was accelerated in the presence of deuterium oxide and inhibited if oxygen in the medium was displaced by nitrogen or azide was added to the medium. Taken together, these data support the view that the plasma membrane is a major target of MC 540-mediated photodamages, that the inactivation of membrane-bound enzymes is an oxidative process, and that at least some photodynamic damages are mediated by type II chemistry.
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PMID:Merocyanine 540-sensitized photoinactivation of soluble and membrane-bound enzymes in L1210 leukemia cells. 217 31

Microwave-stimulated enzyme incubations for acetylcholinesterase, 5'-nucleotidase, alkaline phosphatase, lactate dehydrogenase, malate dehydrogenase, succinic dehydrogenase and isocitric dehydrogenase were studied, and compared with incubations in a waterbath. Temperature settings of 37 degrees C and 50 degrees C were used, and the incubation times were varied from 30 seconds to 30 minutes. The desired temperature of the incubation solution was reached in the microwave oven within 1 minute, whilst in the waterbath it took 10 to 25 minutes. The microscopic results for alkaline phosphatase and succinic dehydrogenase at a temperature setting of 50 degrees C were superior in the microwave method for incubation times less than 15 minutes. It is postulated that the increased reaction product of alkaline phosphatase and succinic dehydrogenase is due to a temperature effect, which has to be large enough to be of practical value. For the other enzymes studied, microwave-stimulated incubations were no better than the conventional incubations at corresponding temperatures. For 5'-nucleotidase there were aspecific lead deposits in the microwave method. All enzymes performed at the elevated, unphysiological temperature of 50 degrees C proved to have advantages, except for 5'-nucleotidase, whilst for malate dehydrogenase there was an aspecific reduction of the colour developer at this temperature.
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PMID:Microwave-stimulated brain enzyme incubations are possible at the unphysiological condition of 50 degrees C. 224 28

Two-dimensional gel electrophoresis (2-D) was used to resolve the plasma membrane proteins from cultured human retinal pigment epithelial cells. The cells were metabolically labeled either with [35S]methionine to reveal proteins in general or with [3H]glucosamine or [3H]fucose which are more specific for glycoprotein visualization. The cell surface proteins were also iodinated, using the lactoperoxidase--glucose oxidase technique. These labeled membranes were separate into plasma membrane-enriched fractions by subjecting the water-shocked postnuclear supernatant to a discontinuous sucrose-density gradient. The five resulting membrane fractions were assayed for protein, RNA (microsomes), galactosyltransferase (Golgi membranes), 5'-nucleotidase (plasma membranes), and succinate dehydrogenase (mitochondrial membranes) and were examined by electron microscopy. The plasma membranes were enriched with minimal contamination at the 0.6-0.85 M (F2) and 0.85-1.0 M (F3) sucrose interfaces based on these biochemical and morphological criteria. Examination of 2-D autoradiographic profiles of F2 and F3 showed that approximately 180 proteins or protein subunits had incorporated [35S]methionine. Certain proteins were also labeled by [3H]glucosamine and [3H]fucose, and surface-labeled by iodination. This was especially true of 17 different high-molecular-weight (43-139 X 10(3) MW) very acidic glycoproteins which formed a constellation of spots. These glycoproteins, as well as others, were also seen in the whole-cell acidic glucosamine-labeled 2-D profiles, where about 150 proteins were detected. A total of 39 proteins were catalogued, of which 34 were detectable in the plasma membrane-enriched fractions. The results show that the use of subcellular fractionation, specific precursors, and labeling techniques aids in the detection and characterization of minor proteins in 2-D gels.
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PMID:Isolation and characterization of plasma membrane proteins of cultured human retinal pigment epithelium. 243 67

Inositol 1,4,5-trisphosphate [Ins(1,4,5)P3], arising from hydrolysis of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], is proposed as the link between membrane-receptor activation and mobilization of Ca2+ from intracellular sites in hormone-secreting cells. The location of Ins(1,4,5)P3-sensitive membranes was investigated in cultured neonatal beta-cells. Membranes were obtained after lysis of cells attached to positively charged Sephadex. After lysis the presence of the enzyme markers 5'-nucleotidase, glucose-6-phosphatase, NADH-cytochrome c reductase, UDP-galactosyltransferase and succinate dehydrogenase indicated the mixed nature of the preparation. After sonication, however, UDP-galactosyltransferase and succinate dehydrogenase activities were undetectable, but 4.8% of total cellular glucose-6-phosphatase and 3.4% of total cellular NADH-cytochrome c reductase remained with 5'-nucleotidase in the preparation, indicating endoplasmic-reticulum association. ATP-dependent 45Ca2+ accumulation was shown in this preparation (410 +/- 24 pmol/mg of protein at 150 nM free Ca2+) and was inhibited by vanadate (100 microM). Ca2+ release was effected by Ins(1,4,5)P3, with half-maximal release at 0.5 +/- 0.14 microM-Ins(1,4,5)P3, t1/2 11.2 +/- 1.1 s. GTP- and guanosine 5'-[beta gamma-imido]triphosphate (p[NH]ppG)-promoted release of 45Ca2+ was demonstrated in this preparation, but the kinetics of release (half-maximal Ca2+ release at 5.4 +/- 0.7 microM, with t1/2 77.3 +/- 6.9 s, and at 51.1 +/- 4.2 microM, with t1/2 19.0 +/- 2.2 s, for GTP and p[NH]ppG respectively), and the ability of neomycin sulphate to block p[NH]ppG-induced release only, are indicative of separate release mechanisms after treatment with these agents. A close association between plasma membrane and elements of the endoplasmic reticulum is indicated in this model, providing a possible mechanism for local alterations in free Ca2+ in the sub-plasma-membrane region.
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PMID:GTP- and inositol 1,4,5-trisphosphate-induced release of 45Ca2+ from a membrane store co-localized with pancreatic-islet-cell plasma membrane. 245 19

Exocrine acinar cells possess two cytochemically distinct populations of secondary lysosomes. One population is Golgi associated and has demonstrable acid phosphatase (AcPase) activity, whereas the second is basally located and lacks AcPase activity but has trimetaphosphatase (TMPase) activity. The basal lysosomes are tubular in shape and rapidly label with horseradish peroxidase (HRP) after intravenous injection. In the present study using isolated rat parotid acinar cells, the two lysosomal populations were separated by cell fractionation on Percoll density gradients and were analyzed biochemically and by EM cytochemistry. On 35% Percoll gradients, two peaks of AcPase and beta-hexosaminidase, both lysosomal marker enzymes, and succinic dehydrogenase, an enzyme marker for mitochondria, could be resolved. The major peaks of beta-hexosaminidase and succinic dehydrogenase and the minor peak of AcPase corresponded with the dense lysosome fraction. The major peak of AcPase and the minor peaks for beta-hexosaminidase and succinic dehydrogenase coincided with the light membrane fraction. Galactosyl transferase (a marker enzyme for Golgi saccules) and 5'-nucleotidase (a plasma membrane marker) were also associated with this fraction. By electron microscopy, the light membrane fraction was seen to contain tubular elements, multivesicular bodies (MVB), Golgi saccules, GERL, immature secretory granules, and some mitochondria. Electron microscopic cytochemical examination showed that these tubular structures were lysosomes. The dense lysosome fraction contained lysosomes positive for both AcPase and TMPase. After continuous incubation of isolated acinar cells with HRP, reaction product was rapidly localized to the light membrane fraction (greater than 2 min), where it was found in vesicles and tubular lysosomes. By 10 min it was present in MVB and tubular lysosomes, but by 60 min no HRP reaction product had appeared in the dense lysosomes. These results demonstrate that the tubular lysosomes are separable from dense lysosomes, typical secondary lysosomes, and are involved in the initial stages of endocytosis.
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PMID:Density gradient separation of two populations of lysosomes from rat parotid acinar cells. 255 1

Cardiac contractile function is dependent on the integrity and function of the sarcolemmal membrane. Swimming exercise training is known to increase cardiac contractile performance. The purpose of the present study was to examine whether a swimming exercise program would alter sarcolemmal enzyme activity, ion flux, and composition in rat hearts. After approximately 11 wk of exercise training, cardiac myosin and actomyosin Ca2+-adenosinetriphosphatase (ATPase) activity was significantly higher in exercised rat hearts than in sedentary control rat hearts. Glycogen content was increased in plantaris and gastrocnemius muscles from exercised animals as was succinic dehydrogenase activity in gastrocnemius muscle of exercised rats in comparison to sedentary rat preparations. Sarcolemmal vesicles were isolated from hearts of exercise-trained and control rats. Sarcolemmal Na+-K+-ATPase and K+-p-nitrophenylphosphatase activities, Na+-Ca2+ exchange, and passive Ca2+ binding did not differ between the two groups. ATP-dependent Ca2+ uptake and 5'-nucleotidase activity were elevated in the cardiac sarcolemmal vesicles isolated from exercised animals compared with sedentary control rats. Sarcolemmal phospholipid composition was not altered by the exercise training. Our results demonstrate that swimming training in rats does not affect most parameters of cardiac sarcolemmal function or composition. However, the elevated sarcolemmal Ca2+ pump activity in exercised rats may help to reduce intracellular Ca2+ and augment cardiac relaxation rates. The enhanced 5'-nucleotidase activity may stimulate adenosine production, which could affect myocardial blood flow. The present results further our knowledge on the subcellular response of the heart to swimming training in the rat.
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PMID:Effects of chronic swimming training on cardiac sarcolemmal function and composition. 273 62


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