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)

Differences in morphogenetic and metabolic activities of the arterial smooth muscle cells (s.m.c.) of the young rat's aorta and femoral artery were studied by histochemical, radiochemical and quantitative radioautographic methods. 3H-proline was found to be incorporated into the medial myocyte of both vessels and released into the extracellular connective tissue matrix during the first 6 hours. The intracellular and extracellular phases of this process were similar to those of other scleroprotein-synthesizing cells. The 3H-proline incorporation, the metachromasia (GAG) and the activities of acetyl-cholinesterase, beta-glucuronidase, aryl-sulfatase and 5'-nucleotidase were more intense in the aortic media. On the other hand, some oxido-reductases linked with cellular respiration, glycogenolysis and energy production as well as the myosin-ATPase and MAO activities are more intense in the femoral artery. These differences suggest the morpho-functional diversity of the arterial s.m.c.: greater morphogenetic activity of the aortic myocyte; earlier and higher contractile differentiation of the femoral one.
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PMID:Segmental differences in morphogenetic activity of arterial smooth muscle cells. Histochemical and radioautographic studies. 15 89

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

New light microscopic visualization methods were developed for the histochemical detection of non-specific alkaline and acid phosphatase, Mg-, Ca- and Na, K-dependent adenosine triphosphatase, myosin adenosine triphosphatase, glucose-6-phosphatase, 5'-nucleotidase and thiamine pyrophosphatase with cerium ions as trapping agents in cryostat and plastic sections. The techniques are based on the conversion of cerium phosphate into cerium perhydroxide by H2O2 which decomposes at 55 degrees-60 degrees C into cerium hydroxide and oxygen radicals. These radicals are able to oxidize diaminobenzidine (DAB) to DAB brown. Addition of nickel ions to the DAB-H2O2 mixture generates bluish-black stained nickel-DAB complexes. Compared with the classical metal precipitation, azo, azoindoxyl and tetrazolium procedures the H2O2-DAB and especially the H2O2-DAB-nickel methods provided identical or superior results in catalytic phosphatase histochemistry and immunohistochemistry when using non-specific alkaline phosphatase as the enzyme label.
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PMID:The cerium perhydroxide-diaminobenzidine (Ce-H2O2-DAB) procedure. New methods for light microscopic phosphatase histochemistry and immunohistochemistry. 285 63

Evidence is presented for a direct interaction of the intrinsic membrane protein 5'-nucleotidase (5'-ribonucleotide phosphohydrolase, EC 3.1.3.5) purified from avian smooth muscle (chicken gizzard) and the cytoskeletal component actin. Two different modes of interaction can be discerned: firstly, an immediate inhibitory effect of preferentially filamentous actin (F-actin) on the enzymic (i.e., AMPase) activity of 5'-nucleotidase and a direct binding of this enzyme to immobilized F-actin. Since these effects are suppressed by the addition of myosin subfragment 1, binding of 5'-nucleotidase appears to occur along the F-actin filament axis. Secondly, a time- and 5'-nucleotidase concentration-dependent transformation of also preferentially F-actin into a form unable to inhibit the enzymic activity of deoxyribonuclease I (DNAase I). This desensitization of actin versus DNAase I is not due to a denaturation process and was found to be reversible after addition of ATP. Furthermore, it does not seem to effect the ability of actin to bind to DNAase I. The transformation is accompanied by the hydrolysis of actin-bound nucleotide into adenosine, which remains bound to actin. Therefore, the desensitization of actin versus DNAase I appears to be due to a nucleotide-dependent conformational change of actin. An unidentified contamination of the 5'-nucleotidase preparations to a varying degree with ADPase and ATPase activities appears to be responsible for the desensitization process, although a synergistic role of these activities and 5'-nucleotidase cannot be excluded.
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PMID:The interaction of 5'-nucleotidase purified from chicken gizzard and actin, and the reversible loss of the inhibitory capacity of actin on deoxyribonuclease I. 298

A plasma membrane fraction from bovine carotid arteries has been isolated by extraction of a crude microsomal fraction with a low-ionic-strength buffer containing ATP and Ca2+. This step was followed by sucrose-density-gradient centrifugation in the presence of 0.6 M KCl. The plasma membrane vesicles were enriched 60- to 80-fold in Na+-K+-adenosinetriphosphatase, 5'-nucleotidase, and phosphodiesterase I activities. The final yields of these marker enzymes were 12-18% of the total activities in the postnuclear supernatant, and the protein yield was 100-120 micrograms/g wet wt of carotid arteries. Contamination of the plasma membrane fraction by mitochondria and sarcoplasmic reticulum was low as judged by low activities of succinate--cytochrome-c reductase and NADPH--cytochrome-c reductase, respectively. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoprecipitation with smooth muscle-specific actin antibodies showed that the plasma membrane fraction was substantially free from myosin and actin contamination. The plasma membrane vesicles accumulated Ca2+ in the presence of ATP, and the accumulation was increased by calmodulin. Ca2+ accumulated in the presence or absence of calmodulin could be released almost completely from the vesicles by the addition of the Ca2+ ionophore A23187 but not by ethyleneglycol-bis(beta-aminoethylether)-N,N'-tetraacetic acid, indicating that Ca2+ uptake in the presence of ATP is intravesicular. The effects of phosphate and oxalate on Ca2+ uptake in the plasma membranes were different from one another. Phosphate increased Ca2+ uptake in a concentration- and time-dependent manner, and the increase in Ca2+ uptake could be observed as early as 1 min. On the other hand, oxalate at concentrations up to 5 mM did not increase Ca2+ uptake significantly during the 30-min incubation. These plasma membranes can prove useful for the study of ion transport across plasma membranes, hormone binding, characterization of calcium channels, and preparation of antibodies against plasma membrane proteins.
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PMID:Isolation and characterization of plasma membranes from bovine carotid arteries. 300 86

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

Homogenates of the posterior latissimus dorsi muscle, a phasic muscle, were fractionated by a one-step zonal centrifugation technique into four major organelle populations and cytoplasmic constituents. These were: (1) Plasma membrane fragments with a modal equilibrium density of 1.10 and containing 5'-nucleotidase, alkaline phosphodiesterase, p-nitrophenylphosphatase and acid phosphatase (beta-glycerophosphate was used as the substrate). (2) Sarcoplasmic reticular fragments which could be further subdivided into calcium transport vesicles, with a model equilibrium density of 1.16, that exhibited calcium uptake; K+-ATPase; leucyl-bet-naphthylamidase; acid phosphodiesterase; acid phosphatase (using cytidine monophosphate as the substrate); and sarcoplasmic reticular lysosomes, with a model equilibrium density of 1.18, possessing dipeptidyl-aminopeptidase II, cathepsin D, alpha-glucosidase, N-acetyl-beta-glucosaminidase, and NADH oxidase activity. (3) Mitochondria with a modal equilibrium density of 1.21. (4) Catalase-containing vesicles with a modal equilibrium density of 1.22; and cytoplasmic constituents (modal density of 1.25) with phosphorylase, pyruvate kinase, myosin-ATPase, aldolase, and protein and RNA content. The purity of these organelles was equal to or better than previous efforts, with a 30-fold purification achieved for 5'-nucleotidase and alkaline phosphodiesterase. These results lend support to the hypothesis that the sarcoplasmic reticulum of phasic muscle, in addition to its specialized role in excitation-contraction coupling, represents a multifunctional membrane system, and that, similar to the smooth endoplasmic reticulum of other cells, it includes some membrane-bound lysosomal enzymes and NADH oxidase.
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PMID:Isopycnic-zonal centrifugation of plasma membrane, sarcoplasmic reticular fragments, lysosomes, and cytoplasmic proteins from phasic skeletal muscle. 721 87

AMP-deaminase (AMPDA) catalyzes the deamination of AMP to IMP and ammonia. Being an integral enzyme of the purine nucleotide cycle (PNC), AMPDA participates in catalytic deamination of amino acids and provides their involvement in a carbohydrate metabolism, fumarate being one of the end products of PNC. Since AMPDA competes with 5'-nucleotidase for AMP, it is responsible for regulation of a physiologically important active product of purine nucleotide metabolism, such as adenosine. Thus, this enzyme plays an important role in determining the physiological state of the organism in normal conditions as well as under the influence of some environmental factors and in some pathologies. The review sums up the information concerning the AMPDA participation in PNC operation in animal tissues, coding genes and enzyme activity regulation by various effectors, including, reversible phosphorylation and binding to myofibrils and myosin. Special attention is being given to a possible relationship of AMPDA activity deficiency to some neuromuscular pathologies.
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PMID:[Functional role and properties of AMP-deaminase]. 871 92

Cellular mechanisms regulating myometrial intracellular free calcium (Ca2+(i)) are addressed in this review, with emphasis on G-protein-coupled receptor pathways. An increase in myometrial Ca2+(i) results in phosphorylation of myosin light chain, an increase in myosin adenosine monophosphatase (ATPase) activity and contraction. Dephosphorylation of myosin light chain and a decline in Ca2+(i) are associated with relaxation. Increases in Ca2+(i) are controlled by multiple signaling pathways, including receptor-mediated activation of phospholipase Cbeta (PLCbeta), leading to release of Ca2+ from intracellular stores. Ca2+ also enters myometrial cells through plasma membrane Ca2+ channels. Conversely, adenosine triphosphate (ATP)-dependent Ca2+ pumps lower Ca2+(i) concentrations and potassium channels promote hyperpolarization that can decrease Ca2+ entry. Receptor-coupled pathways that promote uterine relaxation primarily involve activation of cyclic adenosine monophosphate (cAMP)- or cyclic guanosine monophosphate (cGMP)-stimulated protein kinases that phosphorylate proteins regulating Ca2+ homeostasis. cAMP has inhibitory effects on myometrial contractile activity, agonist-stimulated phosphatidylinositide turnover and increases in Ca2+(i). Some of these effects require association of protein kinase A (PKA) with a plasma membrane-associated A-kinase-anchoring-protein (AKAP). Near term in the rat, there is a decline in the plasma membrane localization of PKA associated with this anchoring protein. This correlates with changes in the regulation of signaling pathways controlling Ca2+(i). L-type voltage-operated Ca2+ entry is an important regulator of myometrial contraction. In addition, putative signal-regulated or capacitative Ca2+ channel proteins, TrpCs, are expressed in myometrium, and signal-regulated Ca2+ entry is observed in human myometrial cells. This Ca2+ entry mechanism may play a significant role in the control of myometrial Ca2+(i) dynamics and myometrial contraction. The regulation of myometrial Ca2+(i) is complex. Understanding the mechanisms involved may lead to design of tocolytics that target multiple pathways and achieve improved suppression of premature labor.
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PMID:Molecular signaling through G-protein-coupled receptors and the control of intracellular calcium in myometrium. 1620 24