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)

Plasma membranes (PM) were isolated from island-forming types of rat ascites hepatoma (AH 130, AH 602, and AH 7974) and from their free-cell sublines (AH 130FN and AH 7974F), and were characterized in terms of electron-microscopic morphology, marker enzyme activities, and lipid contents. The results were compared with those of the PM isolated in a similar way from newborn, regenerating, and adult livers. The marker enzyme activities, such as Na+, K+-insensitive Mg2+-ATPase [EC 3.6.1.3] (Mg2+-ATPase) and 5'-nucleotidase [EC 3.1.3.5], as well as the phospholipid composition of the PM isolated from hepatomas by Wallach's nitrogen gas cavitation method were similar to those obtained with the PM isolated by a modification of Emmelot's method, although the former method gave a much lower yield in terms of protein than the latter. Based on the modified Emmelot method, sufficiently pure PM preparations could be obtained from the hepatomas in the form of large membrane sheets without any contamination by other identifiable components, as determined with an electron microscope, and with high specific activities of the marker enzymes, such as Na+, K+-sensitive ATPase [EC 3.6.1.3] (Na+, K+ -ATPase), Mg2+ -ATPase, and 5'-nucleotidase. As for the characteristics of the hepatoma PM, lower specific activity of 5'-nucleotidase and higher fatty aldehyde molar percentages in total phospholipids were noted in all the PM from the hepatomas in comparison with normal liver PM of various origins. The PM from the hepatomas showed an increased amount of cholesterol (mumole per mg protein), whereas actively growing newborn and regenerating livers gave rather lower amounts in comparison with that of normal adult liver.
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PMID:Isolation and characterization of the plasma membranes from rat ascites hepatomas and from normal rat livers, including newborn, regenerating, and adult livers. 17 89

1. Enzymes, proteins, glycoproteins and lipids of rodent bile were compared with those of a plasma-membrane subfraction originating from the hepatocyte bile-canalicular membrane. 2. Three bile-canalicular glycoprotein enzyme activities were detected in bile. Comparison of the pH optimum and immunoinhibition properties of membrane and bile 5'-nucleotidase activity indicated that they were the same enzyme. Correspondence between membrane and bile alkaline phosphodiesterases also suggested that they were the same enzymes. Activities of Mg2+-stimulated adenosine triphosphatase, a lipid-dependent intrinsic membrane protein, and galactosyltransferase, a Golgi membrane marker, were not detected in bile. 3. Rodent bile contained 15 polypeptide bands that differed radically from those of bile-canalicular membranes. Bands that may correspond in molecular weight to liver plasma-membrane glycoproteins were present at low staining intensities in bile. A major protein of apparent molecular weight 49 500 was present, and albumin was detected by immunodiffusion. 4. The lipid composition of bile and bile-canalicular membrane also differed. Phosphatidylcholine accounted for 82% of rat bile phospholipids, and only trace amounts of phosphatidylinositol, phosphatidylserine and sphingomyelin were present. 5. The results indicate that in healthy animals, the bile-canalicular membrane is refractory to the action of bile acids during the secretory process. The presence of only small amounts of bile-canalicular membrane components, especially glycoprotein enzymes located at the outer face of the membrane, suggests that these are released from the membrane by bile acids after secretion of bile into the canalicular spaces.
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PMID:Role of membranes in bile formation. Comparison of the composition of bile and a liver bile-canalicular plasma-membrane subfraction. 18 22

Activities of a broad spectrum of enzymes were studied histochemically in renal adenocarcinomas induced in young male F344 rats by chronic dietary administration of the carcinogen N(4'-fluoro-4-biphenylyl)acetamide. Enzymes included were: dehydrogenases of glucose-6-phosphate, lactate, succinate, malate, and alpha-glycerophosphate; peroxidase (catalase); glucose-6-phosphatase; alkaline and acid phosphatase; Mg2+ ATPase; 5'-nucleotidase; and aminopeptidase. Levels of enzyme activity were estimated visually and scored from 0 (not detectable) to a maximum of 5 (intense). Comparison of estimated activity for each enzyme was made between small neoplastic nodules (stage III tumors) and large adenocarcinomas (stage IV tumors) and between tumors and portions of normal proximal tubules in parenchyma of kidneys from untreated control rats. The results, which revealed nearly identical levels of activity for most enzymes in both stages III and IV tumors, suggested similar metabolic and biologic behavior of these lesions. However, when data for tumors were compared with data for normal proximal tubules, striking differences were observed consistent with: 1) a marked shift of energy metabolism from oxidative to glycolytic production of ATP, with a corresponding reduction in mitochondrial respiration; and 2) simplification of plasma membrane specializations that were possibly associated with a reduction or loss of transport function. These findings were compared with other histochemical, biochemical, and ultrastructural studies of renal adenocarcinomas in rats and man.
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PMID:Adenocarcinoma of the kidney. II. Enzyme histochemistry of renal adenocarcinomas induced in rats by N-(4'-fluoro-4-biphenylyl)acetamide. 18 77

Ectodermal cells of the two- and three-germ layer-thick mouse egg-cylinders are considered to be the progenitors of embryonal carcinoma cells in embryo-derived teratocarcinomas. In an attempt to find differences between the tumor cells and equivalent embryonic cells, we have studied the electron microscopic cytochemical localization of alkaline phosphatase, 5'-nucleotidase, and Mg2+-activated adenosine triphosphatase (ATPase) in embryo-derived teratocarcinomas and mouse egg-cylinders. Alkaline phosphatase was detected in both embryonic and tumor cells, but its activity appeared much more intense in the tumor cells. No ATPase was demonstrated in embryonic ectodermal cells of 6-day-old embryos and only in occasional cells of 7- and 8-day-old embryos. No 5'-nucleotidase activity could be demonstrated in 6- to 8-day-old cylinders. There was marked ATPase and 5'-nucleotidase activity in the membranes of embryonal carcinoma cells. These data point out some differences on the plasma membrane between the embryonal carcinoma cells and equivalent embryonic cells. The potential significance of these differences is discussed with regards to the transformation of embryonic cells in tumor cells. (Am J Pathol 87:297-310, 1977).
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PMID:Ultrastructural localization of membrane phosphatases in teratocarcinoma and early embryos. 19 83

The excretory canals of Ascaridia galli (Nematoda) and the protonephridial ducts of Cotylophoron cotylophorum (Trematoda) and Raillietina cesticillus (Cestoda) have been studied with regard to the histochemical localization of lipids, carbohydrates and hydrolytic enzymes. Distinct excretory organs are absent in the acanthocephalan Centrorhynchus corvi. Triglycerides, phospholipids and lipoproteins are seen in association with the wall of excretory canals of A. galli and R. cesticillus, and phospholipids and lipoproteins at the corresponding site in C. cotylophorum. The physiological significance of lipids in association with excretion of substances has been discussed. Low molecular weight glycogen is present in the lumen of excretory canal of A. galli but not in other worms. The common feature of the excretory canals is the presence of enzyme activities of nonspecific alkaline phosphatase and Mg2+-dependent ATPase. Activity of acid phosphatase is seen only in the excretory canals of A. galli. Glucose-6-phosphatase is present in A. galli and C. cotylophorum and absent in R. cesticillus. Weak reaction of 5'-nucleotidase is present in the excretory canals of helminth species studied here. The role of these enzymes in transportation of substances across the wall of excretory canals and also in ionic regulation has been discussed in detail.
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PMID:Comparative histochemical observations on the excretory system of helminth parasites. 19 23

Activity of enzymes catalizing bioenergetic processes of substance transport through cell membranes, adenosine triphosphatase and para-nitrophenyl phosphates, activity of certain enzymes of carbohydrate metabolism, lactate dehydrogenase and glucose-6-phosphate dehydrogenase, as well as to 5'-nucleotidase taking part in nucleic metabolism were determined in the pancreas of thyreoidectomized rats. Simultaneously the content of lactic acid, phosphorus, potassium and sodium, which immediately related to activation of the mentioned enzymes, was determined in the pancreas. In thyroidectomized rats the activity of Mg2+, Na+, K+-ATPase, Na+, K+-ATPase and lactate dehydrogenase in the pancreas increases, that of glucose-6-phosphate dehydrogenase, para-nitrophenylphosphatase and 5-nucleotidase decreases, the content of lactic acid, potassium, sodium and phosphorus increases.
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PMID:[Adenosine triphosphatase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase activity of pancreas of thyroidectomized rats]. 20 6

The properties of a number of enzyme activities of the superovulated rat ovary have been studied to establish optimal assay conditions and specific assay procedures for each activity. The activities were chosen on the basis of their extensive use in other tissues of the rat as marker enzymes for the major cell organelles. Homogenates of superovulated rat ovaries were subjected to fractionation by differential rate centrifugation, and sedimentation profiles were constructed for each marker enzyme activity. The various subcellular fractions were also monitored by electron microscopy. The enrichment of fractions with particular organelles by electron microscopy, and enrichment of the appropriate organelle marker enzyme activities correlated well. Sedimentation profiles of a number of plasma membrane marker enzymes demonstrated a marked discrepancy between hCG-binding activity, and 5'-nucleotidase-, alkaline phosphatase-, and Mg2+-dependent ATP-ase on the one hand, and basal, hCG-stimulated, and fluoride-stimulated adenylate cyclase activities on the other hand. Fractions enriched in hCG-binding and adenylate cyclase activities were subjected to further fractionation on discontinuous sucrose density gradients. The distributions of the various plasma membrane markers again indicated a partial dissociations between hCG-binding and adenylate cyclase activities of luteinized rat ovaries, suggesting the existence of two distinct major plasma membrane populations, with different buoyant densities, marker enzyme profiles and adenylate cyclase and hormone-binding levels.
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PMID:Interactions of gonadotropins with corpus luteum membranes. I. Properties and distributions of some marker enzyme activities after subcellular fractionation of the superovulated rat ovary. 21 56

Fractions enriched in hCG-binding activity were prepared by differential rate centrifugation of superovulated rat ovarian homogenates and were applied to continuous sucrose density gradients (20-55%). After centrifugation at 63,000 x gav for 3.5 h, fractions of each gradient were collected and assayed for a range of marker enzyme activities characteristic of surface membranes and subcellular organelles. Mitochondria, lysosomes, and rough and smooth endoplasmic reticulum membranes accumulated in the gradient between 38-41% sucrose (1.165-1.180 g/cm3). Nuclei passed through the gradient. However, the various surface membrane markers concentrated in two distinct regions of the gradient. Alkaline phosphatase, phosphodiesterase, (Na+ + K+)ATPase I, and hCG-binding activity concentrated at 29-32% sucrose (1.120-1.135 g/cm3), whereas 5'-nucleotidase, Mg2+-dependent ATPase, and adenylate cyclase activities (and minor peaks of hCG-binding and phosphodiesterase activities) were enriched at 36-38% sucrose (1.16-1.17 g/cm3). A second ATPase, [(Na+ + K+)ATPase II], was also observed in this region of the gradient, which could be distinguished from (Na+ + K+)ATPase I of the light membrane fraction by its sensitivity to the Ca2+-chelating agent, ethylene glycol bis-(aminoethyl)tetraacetic acid (EGTA). The kinetics of binding of radioiodinated hCG to the gonadotropin receptors of the light and heavy membrane fractions were very similar. It is suggested that fractionation of superovulated rat ovaries yields two distinct populations of surface membrane material which have distinct densities and marker enzyme profiles. Furthermore, in contrast to the heavy membrane fraction, light membranes seem to possess considerable amounts of hCG receptor activity but very little adenylate cyclase.
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PMID:Interactions of gonadotropins with corpus luteum membranes. II. The identification of two distinct surface membrane fractions from superovulated rat ovaries. 21 57

The activities of dTMP kinase (ATP-deoxythymidine monophosphate phosphotransferase, EC 2.7.4.9), 5'-nucleotidase (5'-ribonucleoside phosphohydrolase, EC 3.1.3.5), adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4), AMP deaminase (AMP aminohydrolase, EC 3.5.3.6) and ATP-(Mg2+)-ase (ATP phosphohydrolase, EC 3.6.1.3) were assayed in mitochondria of normal and regenerating rat liver. In regenerating mitochondria, the dTMP kinase activity increased 20 times, 5'-nucleotidase (5'Nase) activity for dTMP diminished by 65% and its activity for other nucleoside monophosphates did not change; adenosine deaminase activity for adenosine (AR) increased by 40%, but for deoxyadenosine (AdR) decreased by 70%. AMP deaminase and ATP-(Mg2+)-ase activities behaved similarly in mitochondria from regenerating liver, decreasing by 70 and 64% respectively. The changes of the amount of dTMP in mitochondria depend on enzyme activities which regulate the AdR concentration.
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PMID:Relationship between 5'-nucleotidase, adenosine deaminase, AMP deaminase, ATP-(Mg2+)-ase activities and dTMP kinase activity in rat liver mitochondria. 22 41

A 5'-nucleotidase with unique specificity has been identified in the soluble fraction of normal human erythrocytes. It mediates the hydrolytic dephosphorylation of pyrimidine 5'-ribosemonophosphates but is catalytically ineffective with purine nucleotides or with the 2'-, 3'-, or cyclic isomers of pyrimidine nucleotides. Activities at 37 degrees in dialyzed hemolysates of nromal human erythrocytes averaged 7.3 and 6.2 mumol of Pi liberated per hour per g of hemoglobin for the substrates UMP and CMP, respectively. Activity with TMP as substrate was approximately one-half as much as with UMP or CMP. Apparent Michaelis constants were 0.33 mM UMP, 0.15 mM CMP, and 1.0 mM TMP. Magnesium was required for optimal activity, and this cation could not be replaced by Mn2+. Maximum activity was obtained between pH 7.0 and 7.5 with rapid decreases in more alkaline media and moderate decreases with acidification. The enzyme was quite sensitive to heat and was strongly inhibited by AMP, by some purine bases, and by both purine and pyrimidine nucleosides. Divalent cations of heavy metals were also strongly inhibitory, as were agents active against sulfhydryl groups. The presence of substrates and/or 2-mercaptoethanol provided considerable protection against some of these deleterious agents and conditions. Pyrimidine 5'-nucleotidase activity in hemolysates was clearly distinguishable from erythrocyte acid phosphatase and from leukocyte and serum alkaline phosphatases and nucleotidases.
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PMID:Characteristics of a pyrimidine-specific 5'-nucleotidase in human erythrocytes. 24 Aug 46


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