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)

Some physico-chemical properties, specificity and the character of action of rat liver nuclear ribonuclease are studied. The enzyme maximal activity was observed at pH 7.5--8.0, ionic strength 0.02--0.3, Mg2+ being necessary. Nuclease is an oligomer, having molecular weight is 160000--180000 daltons and containing separate associates. Purified enzyme is free of contaminating activities (polynucleotidephosphorylase, DNAse; 5'-nucleotidase, and alkaline phosphatases). It is shown to hydrolyse polyA and RNA for endonuclease type, degradation products being oligonucleotides terminating with 5'-phosphate and 3'-hydroxyl groups. RNAse hydrolyses all phosphodiester bonds in polynucleotides, developing no specificity to the nature of bases. Relative hydrolysis rate for different substrates decreased as follows: polyA greater than yeast RNA greater than polyC greater than polyU greater than 28S rRNA greater than greater than 18S rRNA greater than polyA-polyU. The enzyme may be classified as ribonucleate-5'-nucleotidehydrolase (EC 3.1.4.9.).
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PMID:[Nuclear ribonucleases and post-transcriptional changes of RNA. Specificity and other properties of rat liver nuclear endonuclease]. 1 31

1. Highly sensitive technique are described for the assay of plasma membrane (5'-nucleotidase, alkaline phosphatase), microsomal (neutral alpha-glucosidase, leucyl-2-naphthylamidase) and biliary canalicular (gamma-glutamyltransferase) enzymes and for nine acid hydrolases (acid phosphatase, phosphodiesterase, beta-glucosidase, alpha-glucosidase, alpha-galactosidase, beta-galactosidase, alpha-mannosidase, N-acetyl-beta-glucosaminidase, beta-glucuronidase) in human liver. 2. Optimum and specific assay systems have been developed which give linear kinetics for all enzymes. 3. The range of enzyme activities in samples of human liver, obtained by closed needle biopsy, and sera have been determined.
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PMID:Enzyme activities in human liver biopsies: assay methods and activities of some lysosomal and membrane-bound enzymes in control tissue and serum. 1 4

1. The kinetic properties of the 5'-nucleotidase (EC 3.1.3.5) present in the cytosol of rat liver were investigated in relation to the conversion of adenine nucleotides into uric acid, with particular reference to the stimulation of this process by fructose. The enzyme was assayed by the release of Pi and by a new and more sensitive radiochemical procedure. 2. When IMP was used as substrate, the partially purified enzyme displayed almost hyperbolic kinetics (h = 1.1) with S0.5 = 1.2 mM. Similar kinetics were observed with GMP and other nucleoside 5'-monophosphates, except AMP. 3. Vmax. of the enzyme for AMP was about the same as for IMP, but the kinetics were sigmoidal (h = 1.6) with S 0.5 = 10 mM. 4. The hydrolysis of IMP was inhibited competitively by GMP. IMP, at concentrations up to 0.5 mM, had a paradoxical stimulatory action on the hydrolysis of 2-5 mM-AMP and was inhibitory at higher concentrations. 5. The activity of the enzyme towards AMP and IMP was stimulated by ATP and GTP, and inhibited by Pi. Activators and inhibitor approximately cancelled each others' effects. At pH 7.4, the enzymic activity with 0.2 mM-AMP was undetectable under physiological conditions. 6. It is concluded that, in the liver cell, AMP is not hydrolysed by the soluble 5'-nucleotidase, but that its degradation requires prior deamination to IMP.
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PMID:A kinetic study of the soluble 5'-nucleotidase of rat liver. 1 87

Human skin fibroblasts, grown to confluency in the presence of 32P for random labelling of the phospholipids, showed upon 24 h incubation in the presence of either 8 mM L-serine or 4 mM ethanolamine an increased content of phosphatidylserine (150% of control cells) or phosphatidylethanolamine (116% of control cells), respectively. Concomitantly the phosphatidylcholine correspondingly decreased. Upon cell harvesting and gentle enzyme preparation the base-treated cells demonstrated a significantly higher unstimulated, fluoride- and thyrotropin-stimulated activity of adenylate cyclase. The activities of total ATPase, ouabain-sensitive ATPase, 5'-nucleotidase and gamma-glutamyltransferase remained unaltered. When subjecting enzyme preparations from fibroblasts to ultrasonication the activity of adenylate cyclase decreased progressively with energy applied, whereas the activities of the other enzymes were unaltered ((K+ + Na+)-ATPase, 5'-nucleotidase) or even increased (Mg2+-ATPase, gamma-glutamyltransferase). The results have a bearing upon the regulatory function of the phospholipid microenvironment of membrane-bound enzymes.
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PMID:The influence of changes in the phospholipid pattern of intact fibroblasts on the activities of four membrane-bound enzymes. 1 85

1. Plasma membranes were isolated from ascites hepatoma AH-130 and rat livers with or without partial hepatectomy or bile duct ligation. Reciprocal manifestations of two marker enzymes for plasma membranes were observed in these membrane preparations; alkaline phosphatase activity was found much higher in the hepatoma membrane than in any preparations of the liver membranes, whereas 5'-nucleotidase activity was much lower in the former than in the latter. 2. Effects of lectins and anti-plasma membrane antiserum on these two marker enzymes were examined. The results showed that about 50% of apparent activity of 5'-nucleotidase found in the hepatoma membrane was exhibited by alkaline phosphatase. 3. Localizations of alkaline phosphatase and 5'-nucleotidase in polyacrylamide gels after electrophoresis were demonstrated using 5'-AMP and 5-Br, 4-Cl-indoxylphosphate as substrate. There was a difference in electrophoretic mobility between the alkaline phosphatase of the hepatoma and that of the liver.
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PMID:Contrast manifestation of alkaline phosphatase and 5'-nucleotidase in plasma membranes isolated from rat liver and ascites hepatoma. 2 Sep 52

We assessed, in 98 patients with cancer, the diagnostic value of measuring serum alkaline phosphatase, 5'-nucleotidase, gamma-glutamyltransferase, and glutamate dehydrogenase activities as an aid to detection of liver metastases. All four enzymes showed diagnostic value, but 5'-nucleotidase appeared to have the greatest. It showed the lowest false-positive results (7.4%) with the highest predictive value of a positive test (85.7%) and agreement (81.3%).. gamma-Glutamyltransferase showed the lowest proportion of false-negative results (2.8%), but was the least specific 35% false-positive results). Analysis of various test combinations showed that the best agreement (77.5%) was obtained when the patients were divided into those who had no or only one abnormal test result, and those who had two or more abnormal test results. However, this was not better than the agreement for 5' nucleotidase alone (81.3%). The agreement of 5'-nucleotidase and gamma-glutamyltransferase (i.e., both tests were positive or negative) was excellent (91.4%), but such agreement included only 67% of the patients with liver metastases.
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PMID:Value of alkaline phosphatase, 5'-nucleotidase, gamma-glutamyltransferase, and glutamate dehydrogenase activity measurements (single and combined) in serum in diagnosis of metastasis to the liver. 2 Oct 41

Bacteriophage T5 induced a deoxynucleoside 5'-monophosphatase during its infection of Escherichia coli. The enzyme was purified about 100-fold. It was clearly distinct from the host 5'-nucleotidase activity in its physical characteristics and substrate specificity. The enzyme was active on deoxynucleoside 5'-monophosphates but was not active as a phosphatase on ribonucleotides, deoxynucleoside 5'-triphosphates, deoxynucleoside 3'-monophosphates, or deoxyoligonucleotides. Furthermore, it did not have oligonucleotidase or exonuclease activity. The enzyme could exist in multimeric form but had a monomer molecular weight of about 25,000.
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PMID:Properties of deoxynucleoside 5'-monophosphatase induced by bacteriophage T5 after infection of Escherichia coli. 2 5

An inosine-producing strain of Bacillus subtilis was mutated to resistance against the antagonist of glutamine, DL-methionine sulfoxide. Among the mutants derived, guanosine producers were observed frequently. The best strain, 14119, produced 9.6 g of guanosine per liter at a weight yield of 12% from consumed sugar. Inosine production decreased concomitantly. When resistance was increased further by exposure to higher doses of DL-methionine sulfoxide, another strain, AG169, was obtained that did not excrete inosine but produced increased amounts of xanthosine. In these strains, the specific activity of 5'-nucleotidase was lower and that of inosine 5'-monophosphate (IMP) dehydrogenase was higher than the parent strain. It is speculated that the metabolic flow from IMP to xanthosine 5'-monophosphate proceeds more smoothly than that from IMP to inosine and yields more xanthosine and guanosine.
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PMID:Mutation of an inosine-producing strain of Bacillus subtilis to DL-methionine sulfoxide resistance for guanosine production. 2 11

A method is described for the localization and characterization of phospholipases A1 and A2 (EC3.1.1.4) in Krebs II ascites cells, particularly in the plasma membranes. Cells were lysed with a Dounce homogenizer in an isotonic sucrose medium. Plasma membranes sediment with mitochondria and lysosomes during subcellular fractionation and are finally isolated on a continuous sucrose gradient. The membranes are localized at two levels in the gradient, at densities of 1.06 and 1.15, in which 5'-nucleotidase (EC 3.1.3.5) activity exhibits a 9- and 21-fold purification, respectively. Total contamination by endoplasmic reticulum, lysosomes, and mitochondria is 17 percent for the low-density membrane fraction and 25 percent for the high-density fraction. The phospholipases A present in Krebs II cells are active at pH 4.0 and pH 7.5. At the 2 pH values, they have A1 and A2 specificities. The intracellular distribution of acidic forms is comparable to that of acid phosphatase (EC 3.1.3.1), while neutral forms are localized like lactate dehydrogenase (EC 1.1.1.27). A small proportion of neutral phospholipase A2 has the same repartition on the sucrose gradient as nicotinamide adenine dinucleotide diaphorase (EF 1.6.4.3), an endoplasmic reticulum marker, and as 5'-nucleotidase, a plasma membrane marker.
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PMID:Phospholipases A1 and A2 in subcellular fractions and plasma membranes of Krebs II ascites cells. 2 44

The levels of serum gamma-glutamyl transpeptidase (GGT) and, when appropriate, alkaline phosphatase (AP) and 5'-nucleotidase (NTD) have been measured as a routine in 276 patients with malignant haematological diseases during a 26-month trial period. GGT levels add no prognostic information to the routine haematological surveillance of leukaemia. Polychemotherapy does not appear to be an inducer of liver drug-metabolising microsomal enzymes. Polycythaemia rubra vera, myelofibrosis and chronic lymphocytic leukaemia may cause little change in GGT, AP and NTD levels despite marked hepatomegaly. A raised GGT in Hodgkin's disease and non-Hodgkin lymphoma is generally associated with active and widespread disease, but not necessarily a sign of malignant tissue in the liver. The elevations of GGT in myeloma may be secondary to liver infiltration though this group merits further detailed study.
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PMID:Evaluation of the usefulness of serum gamma-glutamyl transpeptidase levels in the management of haematological neoplasia. 2 19


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