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:3.1.3.5 (5'-nucleotidase)
3,167 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Isolated rat heart sarcolemma was treated with different concentrations of an ionic detergent, deoxycholate (DOC) and ATP hydrolysis in the presence of Ca2+ or Mg2+ was determined. 2. Both Ca2+-dependent ATPase and Mg2+-dependent ATPase activities were decreased in the DOC-treated membranes; however, the depression of Mg2+-dependent ATPase activity was greater than that of Ca2+-dependent ATPase. 3. The differential changes in Ca2+-dependent ATPase and Mg2+-dependent ATPase activities were apparent when incubations with DOC were carried out for different time intervals and at different temperatures. 4. In DOC-treated preparations, the Km value for Ca2+-dependent ATPase was decreased whereas that for Mg2+-dependent ATPase was increased. The half maximal velocities of the Ca2+-dependent ATPase and Mg2+-dependent ATPase enzyme reactions in the treated preparations were obtained at a DOC: membrane protein ratio of 3.0 and 0.6, respectively. 5. In the DOC-treated membranes exhibiting the half maximal velocities of enzyme reactions, the Ka value for Ca2+-dependent ATPase was drastically reduced but remained unchanged for Mg2+-dependent ATPase. 6. The DOC treatment was associated with a loss of protein as well phospholipids and resulted in changes in the ultrastructural integrity of the membrane. 7. Varying degrees of decreases in the activities of sarcolemmal adenylate cyclase. (Na+-K+)-ATPase, 5'-nucleotidase and calcium binding were seen upon DOC treatment. 8. The extent of reduction in Ca2+-dependent ATPase and Mg2+-dependent ATPase activities were also different when the membrane was treated with a non-ionic detergent, Lubrol PX. 9. These data suggest that Ca2+-dependent ATPase in heart sarcolemma is more resistant than Mg2+-dependent ATPase to detergent treatments and further indicate some differences in the properties of these enzymes.
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PMID:Ca2+- and Mg2+-dependent ATPase activities in the deoxycholate-treated rat heart sarcolemma. 612 55

Dieldrin, an organochlorine insecticide, when administered orally to male albino rats at a dose of 5 mg/kg body weight/day for 15 days inhibits the enzyme Mg2+ -ATPase and stimulates the activity of 5'-nucleotidase and NADH-dehydrogenase in liver plasma membrane. L-ascorbic acid supplementation offers some protection in relation to the inhibition of Mg2+ -ATPase.
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PMID:Effect of dieldrin on rat liver plasma membrane enzymes. 612 57

The intracellular localization of adenylate cyclase and 3',5'-cyclic nucleotide phosphodiesterase in buffalo sperm was examined. Adenylate cyclase activity is distributed in heads (8.4%), midpieces (16.6%), tails (49.5%) and 5.7% in the soluble supernatant; the total recovery being 81%. A 4-fold increase in specific activity was observed in the tail fraction relative to sonicated suspension. Further fractionation of the tail fraction into plasma membrane and microtubules by dialysis against low ionic strength buffer was followed by marker enzymes (Mg2+ -ATPase, 5'-nucleotidase and alkaline phosphatase) as well as by examination of fractions under electron microscope. The recovered adenylate cyclase (79%) was found in microtubules (45%) and plasma membrane (34%). Cyclic nucleotide phosphodiesterase in tails was distributed in tail plasma membrane (13.7%), microtubules (31.5%) and cytosol (34%) with a total recovery of 80%. Similar results were obtained when the distribution of adenylate cyclase and cyclic nucleotide phosphodiesterase was studied by treatment with Triton X-100; 40% activity of adenylate cyclase present in tails (about 20% relative to sperm sonicate) appeared in the soluble form by this method. The results are discussed in relation to control of cyclic AMP levels in buffalo sperm by adenylate cyclase and cyclic nucleotide phosphodiesterase.
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PMID:Subcellular localization of adenylate cyclase of buffalo spermatozoa. 612 19

Specific assays for 5'-nucleotidase, adenosine diphosphatase (ADPase) and Mg2+-dependent adenosine triphosphatase (Mg2+-ATPase) have been optimized for human lymphocytes and their subcellular localizations determined by sucrose density gradient centrifugation. 5'-Nucleotidase was localized solely to the plasma membrane of the lymphocyte. ADPase activity has been shown to have a dual localization to the plasma membrane and mitochondria, whilst Mg2+-ATPase was mainly located in the mitochondria. No [Na+,K+] activated Mg2+-dependent ATPase could be measured in these cells. We have confirmed the striking decrease in the specific activity of 5'-nucleotidase activity in lymphocytes from patients with common variable primary hypogammaglobulinaemia. In contrast, the specific activities of ADPase and Mg2+-ATPase showed no alteration in lymphocytes from the patient group when compared to controls. Thus the deficiency of ecto-5'-nucleotidase in the lymphocytes of patients with hypogammaglobulinaemia is a highly selective defect in purine metabolism.
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PMID:Studies on the kinetic properties and subcellular localization of adenine nucleotide phosphatases in peripheral blood lymphocytes from control subjects and patients with common variable primary hypogammaglobulinaemia. 612 80

Although acute alterations in Ca2+ fluxes may mediate the skeletal responses to certain humoral agents, the processes subserving those fluxes are not well understood. We have sought evidence for Ca2+-dependent ATPase activity in isolated osteoblast-like cells maintained in primary culture. Two Ca2+-dependent ATPase components were found in a plasma membrane fraction: a high affinity component (half-saturation constant for Ca2+ of 280 nM, Vmax of 13.5 nmol/mg per min) and a low affinity component, which was in reality a divalent cation ATPase, since Mg2+ could replace Ca2+ without loss of activity. The high affinity component exhibited a pH optimum of 7.2 and required Mg2+ for full activity. It was unaffected by potassium or sodium chloride, ouabain or sodium azide, but was inhibited by lanthanum and by the calmodulin antagonist trifluoperazine. This component was prevalent in a subcellular fraction which was also enriched in 5'-nucleotidase and adenylate cyclase activities, suggesting the plasma membrane as its principal location. Osteosarcoma cells, known to resemble osteoblasts in their biological characteristics and responses to bone-seeking hormones, contained similar ATPase activities. Inclusion of purified calmodulin in the assay system caused small non-reproducible increases in the Ca2+-dependent ATPase activity of EGTA-washed membranes. Marked, consistent calmodulin stimulation was demonstrated in membranes exposed previously to trifluoperazine and then washed in trifluoperazine-free buffer. These results indicate the presence of a high affinity, calmodulin-sensitive Ca2+-dependent ATPase in osteoblast-like bone cells. As one determinant of Ca2+ fluxes in bone cells, this enzyme may participate in the hormonal regulation of bone cell function.
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PMID:A high affinity, calmodulin-responsive (Ca2+ + Mg2+)-ATPase in isolated bone cells. 613 20

Determination of enzymatic activity, protein profile and phospholipid composition of muscle plasma membranes and sarcoplasmic reticulum in rats were carried out after clofibrate injections in a dose of 0.4 g/kg body weight. In the plasma membranes, the activity of Na+ + K+, Mg2+ ATPase was insignificantly decreased, and that of 5'-nucleotidase significantly diminished. A non-significant change was observed in the total amount of phopholipids. The amount of phosphoethanolamine appeared to be lower. Changes in the protein profile were seen. In the sarcoplasmic reticulum, the major abberation was the decrease of Mg2+ ATPase activity. No evident changes were observed in the phospholipid behaviour. Abnormalities in the protein profile appeared. In the myofibrillar proteins, increases of alpha-actinin and troponin at the expense of myosin were observed. In the clofibrate model of myotonia in rats, the changes in the biochemical parameters were less pronounced as compared to the previously tested 20,25-diazacholesterol model.
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PMID:Clofibrate-induced myotonia in rats. 613 23

Heart sarcolemmal membranes were isolated by the hypotonic shock-LiBr treatment from rats with chronic diabetes induced by a streptozotocin (65 mg/kg, iv) injection. Sarcolemmal Mg2+-dependent ATPase activity was elevated, whereas 5'-nucleotidase and K+-p-nitrophenylphosphatase activities in diabetic heart were depressed in comparison to control preparations. Although patent Na+-K+-ATPase and patent ouabain-sensitive Na+-K+-ATPase activities were unaltered, latent Na+-K+-ATPase activities, as determined in membranes after alamethicin or deoxycholate treatments, were found to be significantly depressed in diabetic animals. A depression in the latent Na+-K+-ATPase activity in diabetic preparations was also observed in membranes prepared by the sucrose density gradient method. Insulin-treated diabetic rats were observed to have normalized latent Na+-K+-ATPase activities. Total phospholipid content did not differ, but cholesterol content of the sarcolemmal membranes was significantly increased in diabetic heart preparations. Sarcolemmal Na+-K+-ATPase activity in diabetic heart was more resistant to treatments with filipin, an agent known to bind with cholesterol residues. These results suggest that chronic experimental diabetes is associated with some defects in sarcolemmal enzymatic activities and composition.
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PMID:Sarcolemmal Na+-K+-ATPase activity in diabetic rat heart. 613 47

A high affinity Ca2+-stimulated, Mg2+-dependent ATPase (Ca2+-Mg2+-ATPase) was identified in microsomes and plasma membrane vesicles isolated from rat hepatocytes. The distribution of this enzyme was similar to that of the plasma membrane marker enzymes alkaline phosphodiesterase and 5'-nucleotidase. The Ca2+-Mg2+-ATPase had an apparent half-saturation constant of approximately 75 nM for Ca2+. After incubation of rat hepatocytes with 25 nM vasopressin for 3 min, the activity of Ca2+-Mg2+-ATPase was decreased 15-30%. The effect of vasopressin on the activity of this enzyme was near maximal after incubating hepatocytes with vasopressin for only 15 sec. The concentration of vasopressin needed for half-maximal inhibition of this enzyme in hepatocytes was approximately 6 nM. Treatment of the hepatocytes with 10 microM phenylephrine caused about a 10% decrease in ATPase activity while 10 nM glucagon or 200 microU/ml insulin did not affect the enzyme. These findings suggest that inhibition of the Ca2+-Mg2+-ATPase activity may be part of the mechanism by which vasopressin and alpha-adrenergic agonists elevate cytosolic Ca2+ in hepatocytes.
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PMID:Regulation of Ca2+-Mg2+-ATPase activity in hepatocyte plasma membranes by vasopressin and phenylephrine. 613 76

Effects of adriamycin on rat heart sarcolemma were investigated by determining several membrane enzyme activities in the absence or presence of different concentrations of the drug. The adenylate cyclase activity was found to be stimulated by 0.001 and 0.01 microM of adriamycin whereas this enzyme activity was inhibited at 100 and 1000 microM concentrations of the drug. Magnesium dependent Na+, K+ ATPase was not effected by adriamycin, however, in presence of 2 mM ouabain, adriamycin (100 microM) had a depressant effect on the Na+, K+ ATPase activity. Ca2+ ATPase activity was found to be stimulated by adriamycin. The drug had no effect on the Mg2+ ATPase and 5'-nucleotidase activities. These data suggest direct as well as specific effects of adriamycin which may be important in drug-induced cardiotoxicity.
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PMID:Direct effects of adriamycin on the rat heart sarcolemma. 614 11

The Wachstein and Meisel incubation medium was used to detect ATPase activity in epimastigote, spheromastigote (amastigote), and bloodstream trypomastigote forms of Trypanosoma cruzi. Reaction product, indicative of enzyme activity, was associated with the plasma membrane covering the cell body and the flagellum of the parasite. No reaction product was found in the portion of the plasma membrane lining the flagellar pocket. The plasma membrane-associated ATPase activity was not inhibited by ouabain or oligomycin, was detected in incubation medium without K+, was inhibited by prolonged glutaraldehyde fixation, and its activity was diminished when Mg2+ was omitted from the incubation medium. The Ernst medium was used to detect Na+-K+-ATPase activity in T. cruzi. No reaction product indicative of the presence of this enzyme was detected. Reaction product indicative of 5'-nucleotidase was not detected in T. cruzi. Acid phosphatase activity was detected in lysosomes. Those results indicate that a Mg2+-activated ATPase is present in the plasma membrane of T. cruzi and that it can be used as an enzyme marker, provided that the mitochondrial and flagellar ATPases are inhibited, to assess the purity of plasma membrane fractions isolated from this parasite.
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PMID:Localization of a Mg2+-activated ATPase in the plasma membrane of Trypanosoma cruzi. 614 95


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