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)

The subcellular localization, kinetics of activation, and substrate specificity of the guinea pig granulocyte superoxide (O2-) generating system was investigated. Membrane-enriched particles (podosomes) were made from granulocytes by mild sonication and differential centrifugation. These podosomes are enriched threefold for known plasma membrane markers, 5'-nucleotidase, and adenylate cyclase. Podosomes made from resting granulocytes have very little NAD(P)H-dependent O2- production. Podosomes made from cells stimulated with digitonin are equally enriched for membrane markers but have a 15- to 20-fold increase in NAD(P)H-dependent O2- production. The KmAPP for NADPH is one-tenth that for NADH, but the Vmax is the same. The kinetics of digitonin-stimulated whole-cell O2- production parallel the changes in enzyme activity in these podosomes. Temperature affects both the rate and extent of activation of this enzyme. The pH optimum for the enzyme, the pH optimum for activation, and the pH optimum for whole-cell O2- production are all 7.5. Enzyme activity is increased if the cells are treated with glucose and cyanide, inhibited in cells treated with 2-deoxyglucose (2-DOG), and requires the presence of calcium for activation. These effects are similar to those found for granulocyte O2- production. Thus, the granulocyte O2- generating enzyme system is located on a fraction enriched for plasma membrane markers, and the kinetics of granulocyte production are directly related to the rate and amount of activation of this enzyme.
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PMID:Activation of the guinea pig granulocyte NAD(P)H-dependent superoxide generating enzyme: localization in a plasma membrane enriched particle and kinetics of activation. 624 12

The activity of adenylate cyclase (Ac), cAMP phosphodiesterase (PDE) and 5'-nucleotidase was studied in plasma membranes from the liver of rat embryo of the 20th day of development normally and after exposure to ionizing radiation. Gamma-irradiation of plasma membranes with doses ranging from 0.1 to 100 kR was shown to inhibit the activity of Ac, this effect being more pronounced during stimulation with higher doses of isoproterenol. The activity of 5'-nucleotidase and PDE remained unchanged up to the dose of 100 kR.
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PMID:[Radiation modulation of the activity of the enzymatic systems in isolated plasma membranes in early ontogeny]. 624 41

Liver membrane adenylate cyclase activity was significantly higher and 5'-nucleotidase activity significantly lower in alloxan diabetic rats compared with normal rats.
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PMID:Changes in adenylate cyclase and 5-nucleotidase activities in liver membranes from alloxan diabetic rats. 624 11

The sarcolemmal membranes were isolated by the hypotonic shock-LiBr treatment method from rat, guinea pig, rabbit, and dog hearts and their various biochemical activities were measured. The Mg2+-ATPase, Ca2+-ATPase, and 5'-nucleotidase were most active in rat heart homogenates as well as sarcolemmal membranes, whereas the adenylate cyclase and Na+, K+-ATPase were most active in guinea pig heart preparations. ATP-independent calcium binding activity of rat heart sarcolemma was the same as that of guinea pig heart membrane, whereas ATP-dependent calcium binding of rat heart preparation was negligible. Treatment of sarcolemma with 0.6 M KCl increased the adenylate cyclase and Na+, K+-ATPase activity in rat heart, but these activities were unaltered or decreased in other species. The gel electrophoretic pattern of protein bands and phospholipid composition of rat heart sarcolemma were different from those of guinea pig heart. Sarcolemma isolated from hearts by sucrose gradient method also showed species-dependent difference in the membrane-bound enzyme activities. These results have been interpreted to suggest species-related difference in calcium movements across sarcolemma and this may contribute to determining species-dependent difference in the regulation of myocardial calcium metabolism.
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PMID:Species-related difference in the heart sarcolemmal enzyme activities. 624 42

1. Rat isolated fat-cells were coated with rabbit anti-(rat erythrocyte) antibody and incubated with fresh guinea-pig serum for 25 min at 37 degrees C, which resulted in a more than 95% release of the cytosolic enzyme lactate dehydrogenase. 2. Under these conditions fragmentation of the plasma membrane was examined by following the plasma-membrane markers 5'-nucleotidase, adrenaline-sensitive adenylate cyclase and membrane-bound rabbit immunoglobulin G through a differential-centrifugation fractionation procedure. 3. Approx. 50% of the plasma-membrane markers remained associated with triacylglycerol. Of the remainder more than half was pelleted by centrifugation at 10 000 g for 30 min. 4. The 10 000 g supernatant was fractionated by centrifugation on a sucrose density gradient (15-50%, w/w). This procedure resulted in the production of two visible white bands on the density gradient. The bands consisted of vesicles derived from the plasma membrane, since they coincided with peaks of 5'-nucleotidase activity, contained membrane-bound immunoglobulin G and the denser one had adenylate cyclase activity. The phospholipid and protein contents of the vesicles were determined and compared with those in purified plasma membrane. 5. It is suggested that complement-mediated lysis of rat fat-cells caused the production of plasma-membrane vesicles that differ in composition from the whole plasma membrane.
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PMID:Complement-mediated production of plasma-membrane vesicles from rat fat-cells. 624 63

A simple and rapid method of isolating plasma membranes from rat lungs is described. The method involves homogenization of tissue in isotonic sucrose-buffered medium followed by differential and sucrose density gradient centrifugation. Plasma membranes obtained by this procedure were essentially free from other subcellular contamination. Plasma membranes isolated from 2-day-old rat lungs showed 6 to 7-fold purification of adenylate cyclase and 5'-nucleotidase activities compared to the original homogenate. In contrast, plasma membranes from 35-day-old rat lungs showed no purification of adenylate cyclase activity although 5'-nucleotidase activity showed similar enrichment. These results suggest that adenylate cyclase activity is not a reliable marker for plasma membranes from adult rat lungs.
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PMID:Isolation of plasma membranes from rat lungs: effect of age on the subcellular distribution of adenylate cyclase activity. 624 61

A rat heart sarcolemmal preparation could be obtained in which both 5'-nucleotidase and adenylate cyclase were enriched approx. 9-fold by subjecting a homogenate to a discontinuous sucrose gradient, without the use of a high salt extraction. After incubation of this fraction with Mg[gamma-32P]ATP, the majority of 32P incorporated was present in 24 000- and 9000-dalton protein components. Only when a heart cytosol fraction or a purified cyclic AMP-dependent protein kinase was added, was enhancement of 32P-incorporaton found by addition of cyclic AMP. The 9000- and 24 000-dalton proteins appeared to be interconvertible. The degree of conversion could be affected by changing the temperature during solubilizaion of the membranes in SDS prior to electrophoresis. This suggested that the 24 000-dalton protein does not correspond to phospholamban, first identified by others in canine heart sarcoplasmic reticulum. Moreover, it could be excluded that the 24 000-dalton protein was derived from contaminating myofibrillar troponin I. When the sarcolemmal fraction was preincubated with Ca2+, Mg2+, ATP and oxalate, contaminating sarcoplasmic reticulum vesicles, loaded with calcium oxalate, settled to a greater density in the sucrose gradient. Membrane constituents other than those with enzymatic activity were monitored to confirm the separation between sarcolemmal and sarcoplasmic reticulum membranes: Coomassie blue staining material, sialic acid, cholesterol and phospholipid. The 24 000- and 9000-dalton proteins were equally distributed among the sarolemmal and sarcoplasmic reticulum fractions present in the sucrose gradient. However, the rate of 32P-incorporation in the presence of heart cytosol fraction was much slowr in the sarcoplasmic reticulum than in the sarcolemmal fraction.
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PMID:Phosphorylation of low molecular weight proteins in purified preparations of rat heart sarcolemma and sarcoplasmic reticulum. 625

High voltage free flow electrophoresis has been applied to the separation of human platelet membranes. After short treatment with neuraminidase at the whole cell level, three membrane vesicle subpopulations have been isolated. Using a surface label (125I-labeled Lens culinaris lectin), the marker enzyme NADH-cytochrome c reductase, and lipid analysis, two of the fractions have been identified as of surface origin and the other consists of intracellular membrane elements. The distribution of adenylate cyclase, leucyl aminopeptidase, 5'-nucleotidase and Ca2+-ATPase has also been investigated, and their usefulness as markers for the different membrane fractions has been evaluated. All three fractions are vesicular but differ in size and character. Their phospholipid and cholesterol contents have been determined, and the cholesterol/phospholipid ratios of the two surface fractions are over twice that of the intracellular membrane, which also has a significantly lower microviscosity as determined by fluorescence polarization using diphenyl hexatriene. The polypeptide profiles from sodium dodecyl sulfate-polyacrylamide gel electrophoresis are particularly distinctive, with actin present in the two surface membrane fractions and absent from the intracellular membranes. Myosin, confirmed by its ATPase characteristics, is almost exclusively localized in one of the surface membrane fractions, and actin-binding protein is a prominent feature of the other.
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PMID:Characterization of human platelet surface and intracellular membranes isolated by free flow electrophoresis. 626 Jul 85

The effect of ethanol on membrane enzymes (Na+, K+ and Mg2+ ATPases, 5'-nucleotidase, adenylate cyclase) alcohol dehydrogenase, aldehyde dehydrogenase and superoxide dismutase were studied in nerve cells (established cell lines, primary cultures of chick and rat brain) cultured in the presence of 100 mM ethanol, and in total rat brain, following various ethanol treatments of the rats (20% ethanol as the sole liquid source, intraperitoneal injection). The results show a difference between neuronal and glial cells. Most of the observed changes in enzymatic activities returned rapidly to control values when ethanol was withdrawn from the culture medium or from the diet. Alcohol dehydrogenase was more stimulated by ethanol than aldehyde dehydrogenase; therefore acetaldehyde may be accumulated. The inhibition of superoxide dismutase activity may allow an accumulation of cytotoxic O2- radicals in nervous tissue and may explain the polymorphism of lesions brought about by alcohol intoxication.
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PMID:Ethanol and neuronal metabolism. 626 95

The localization of adenylate cyclase and 5'-nucleotidase activities in the follicular cells of adenomatous goiter and normal thyroid was studied by light and electron microscopy. Simultaneous biochemical measurement for both activities was carried out to confirm the histochemical findings. Adenylyl-imidodiphosphate (AMP-PNP) was used as an effective substrate for adenylate cyclase. The specificity of the adenylate cyclase reaction was also examined by adding oxalacetic acid or PCMB as an adenylate cyclase inhibitor, and by adding sodium fluoride or TSH as an adenylate cyclase stimulator to the reaction mixture. In the case of tissue from adenomatous goiter, a large amount of the reaction product of the adenylate cyclase activity was found uniformly in the apical and lateral plasma membrane and not in the basal plasma membrane. In the cases of normal thyroid, a small amount of the reaction product of adenylate cyclase activity was demonstrated, and only in the lateral plasma membrane of the follicular cells. On the otherhand, the histochemical localization of 5'-nucleotidase activity was the same in adenomatous goiter and normal thyroid. The reaction product of 5'-nucleotidase activity was found predominantly in the apical plasma membrane of the follicular cells. The biochemical findings indicated that the activity of adenylate cyclase per gram tissue was approximately 2 times higher in the case of adenomatous goiter than that in the case of normal thyroid, while the 5'-nucleotidase activity in adenomatous goiter was in slightly higher level than in normal thyroid. Thus the histochemically demonstrable amount of adenylate cyclase and 5'-nucleotidase reflected the activity levels measured biochemically. The lack of demonstrable adenylate cyclase activity in the basal plasma membrane suggests the possibility that this structure may not play any important role in TSH reception.
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PMID:Localization of adenylate cyclase and 5'-nucleotidase activities in human thyroid follicular cells. 628 89


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