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

---

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

Both erythrocytes and leukocytes from a patient with erythrocyte pyrimidine 5'-nucleotidase (P5N) deficiency were shown to contain increased amounts of pyrimidine nucleotides. These findings suggested that the leukocytes were also deficient for P5N. Measurement of the P5N activity in lysates from lymphocytes or granulocytes, in the presence of inhibitors for non-specific 5'-nucleotidase or alkaline phosphatase, indeed showed a deficiency for P5N in lymphocytes and granulocytes of the patient with erythrocyte P5N deficiency. However, the P5N deficiency in the leukocytes did not cause clinical disturbances in addition to the weak haemolytic anaemia.
...
PMID:Deficiency of pyrimidine 5'-nucleotidase in human leukocytes. 255 46

Hair analyses of 80 children with learning and behavioral problems were assessed by age, sex, season, place of residence, exposure to passive smoke and excess contact with known cadmium air pollutant sources. All children had been exposed for at least 2 years to air pollution from a refuse-derived fuel incineration plant. All of the patients had increased hair cadmium compared with a control group, but there was a strong seasonal influence on hair cadmium. Exposure to cadmium was ubiquitous. A neurobehavioral toxic effect was found in children who showed evidence of inhibition of pyrimidine-5'-nucleotidase by low hair phosphorus levels and low zinc levels in whom there was enhanced lead absorption. Hair analyses appear to be a useful biological monitor for detecting toxic effects from ambient air cadmium levels in subsets of the population at risk for heavy metal toxicity. Air filter measurements appear worthless for detecting environmental contamination with cadmium in air with low levels of lead. Trees, on the other hand, which are more adversely affected by cadmium than other heavy metals, show evidence of inhibition of pyrimidine-5'-nucleosidase by excess seeding.
...
PMID:The effect of ambient cadmium air pollution on the hair mineral content of children. 271 25

Residual 5'-nucleotidase activities in hemolysates from nine subjects with severe hereditary deficiency of pyrimidine nucleotidase (PyrNase) were compared to those in normal and reticulocyte-rich controls. Dephosphorylation rates of 12 potential ribo- and deoxyribomononucleotide substrates were measured as a function of pH. Data confirmed the existence of at least two isozymes of 5'-nucleotidase, PyrNase, and 2'-deoxy-5'-ribonucleotide phosphohydrolase (dNase) distinguishable by differences in maximal velocities, substrate preferences and restrictions, and pH optima. PyrNase was confirmed to be active principally with pyrimidine substrates (UMP = dCMP greater than CMP much greater than dTMP greater than dUMP) at a pH optimum of 7.5 +/- 0.1. dNase activity occurred with both purine and pyrimidine substrates and was maximal with deoxy analogs (dIMP much greater than dUMP greater than dGMP greater than dTMP = dAMP much greater than dCMP) at a pH optimum of 6.2, but slight cross-reactivity occurred with some nondeoxy substrates (IMP greater than GMP greater than UMP = XMP greater than CMP). PyrNase and dNase may be complementary systems that serve physiologically to clear the cytosol of RNA and DNA degradation products during maturation of erythroid elements by conversion of nucleotide monophosphates to diffusible nucleosides.
...
PMID:Substrate specificity and pH sensitivity of deoxyribonucleotidase and pyrimidine nucleotidase activities in human hemolysates. 282 57

Recently cytochemical evidence has been presented for a novel enzyme activity, i.e. 'manganese-dependent pyrimidine 5'-nucleotidase (MDPNase)' activity in the rod outer segments (ROS) of rat retinas in situ and in isolated rat ROS. The present biochemical study was undertaken to seek further evidence for this enzyme activity using an independent method. A series of enzyme assays was carried out to test for MDPNase activity in Triton extracts of rat ROS isolated by sucrose density gradient centrifugation. Hydrolysis of the substrate, cytidine-5'-monophosphate, was measured spectrophotometrically and expressed as microgram of released inorganic phosphorus hr-1 mg-1 protein in the sample. The results showed that the ROS extracts contained enzyme activity (18.1 +/- 3.8) that was increased 5-6-fold (102.3 +/- 10.6) in the presence of 7.4 mM MnCl2. The enzyme activity was not enhanced by Mg2+ ions (19.0 +/- 7.7) and was strongly inhibited by 10-20 mM NaF (11.8 +/- 2.9). Assays for substrate specificity revealed that the Mn2+-stimulated phosphatase activity was specific for 5'-nucleotides. Pyrimidine nucleotides (5'-CMP and 5'-UMP) were the preferred substrates. Comparison of enzymatic hydrolysis of 5'-CMP and 5'-AMP over a pH range from 4.5 to 8.0 revealed that at acid pH, the majority of the observed 5'-nucleotidase activity (82% at pH 5.0, 58% at pH 5.5) was manganese dependent, whereas at neutral pH and above, most of the enzyme activity was unaffected by the presence of Mn2+ ions.(ABSTRACT TRUNCATED AT 250 WORDS)
...
PMID:Biochemical evidence for Mn2+-dependent 5'-nucleotidase activity in isolated rod outer segments. 282 95

The growth of transformed mouse fibroblasts (3T6 cells) in medium containing 5% fetal bovine serum was inhibited after treatment with concentrations greater than 50 microM ATP, ADP, or AMP. Adenosine, the common catabolite of the nucleotides, had no effect on cell growth at concentrations below 1 mM. However, the following results indicate that the toxicity of ATP, ADP, and AMP is mediated by serum- and cell-associated hydrolysis of the nucleotides to adenosine. 1) ADP and AMP, but not ATP, were toxic to 3T6 cells grown in serum-free medium or medium in which phosphohydrolase activity of serum was inactivated. Under these conditions, the cells exhibited cell-associated ADPase and 5'-nucleotidase activity, but little ecto-ATPase activity. 2) Inhibition of adenosine transport in 3T6 cells by dipyridamole or S-(p-nitrobenzyl)-6-thioinosine prevented the toxicity of ATP in serum-containing medium and of ADP and AMP in serum-free medium. 3) A 16-24-h exposure to 125 microM AMP or ATP was needed to inhibit cell growth under conditions where serum- and cell-associated hydrolysis of the nucleotides generated adenosine in the medium continuously over the same time period. In contrast, 125 microM adenosine was completely degraded to inosine and hypoxanthine within 8-10 h. Furthermore, multiple doses of adenosine added to the cells at regular intervals over a 16-h period were significantly more toxic than an equivalent amount of adenosine added in one dose. Treatment of 3T6 cells with AMP elevated intracellular ATP and ADP levels and reduced intracellular UTP levels, effects which were inhibited by extracellular uridine. Uridine also prevented growth inhibition by ATP, ADP, and AMP. These and other results indicate that serum- and cell-associated hydrolysis of adenine nucleotides to adenosine suppresses growth by adenosine-dependent pyrimidine starvation.
...
PMID:Growth inhibition of transformed mouse fibroblasts by adenine nucleotides occurs via generation of extracellular adenosine. 284 30

Erythrocytes from patients with hereditary pyrimidine 5'-nucleotidase (P5N, EC 3.1.3.5) deficiency accumulate large quantities of several pyrimidine nucleotides and their derivatives. In addition, the reduced glutathione (GSH) concentration is elevated in erythrocytes from patients with this enzyme deficiency. In the present study, we were unable to demonstrate any effect of various pyrimidine nucleotides and their derivatives on enzymes of glutathione biosynthesis and metabolism. Thus, elevation of GSH levels in erythrocytes from P5N patients is not a result of modulation of these enzymes by pyrimidine nucleotides and their derivatives.
...
PMID:Pyrimidine nucleotides do not affect the enzymes of glutathione biosynthesis. 286 97

Zymosan particle-stimulated beta-galactosidase secretion by mouse peritoneal macrophages was found to be inhibited by micromolar concentrations of adenosine, AMP, ADP, and ATP. Inhibition by all four agents was increased to approximately 80% by adding erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA; 10 microM) an adenosine deaminase inhibitor, to the incubation medium. The inhibition of lysosomal enzyme secretion by ATP, ADP, and AMP was reversed by adding alpha, beta -methylene ADP (100 microM), a 5'-nucleotidase inhibitor, to the incubation medium. Inhibition by adenosine, however, was unaffected by alpha, beta -methylene ADP indicating that the inhibition by AMP, ADP, and ATP only occurred after they had been converted to adenosine by cell surface phosphohydrolases, including 5'-nucleotidase. Theophylline, a competitive antagonist of the binding of adenosine to plasma membrane adenosine receptors, failed to reverse the inhibitory effect of adenosine indicating the probable site of adenosine action to be intracellular. Other purine nucleosides, e.g., guanosine, and several purine and ribosemodified structural analogues of adenosine also inhibited zymosan-stimulated beta-galactosidase secretion, while xanthosine and certain pyrimidine nucleosides, e.g., thymidine, were inactive in this respect.
...
PMID:Regulation of macrophage lysosomal secretion by adenosine, adenosine phosphate esters, and related structural analogues of adenosine. 298 3

Since the red cell enzyme pyrimidine-5'-nucleotidase (PN) is inhibited by lead, we examined the feasibility of using the activity of this enzyme as a measure of lead exposure. Erythrocyte PN activity was measured in 110 blood samples obtained from subjects working in industries which utilize lead and 40 control subjects. The measurements were then compared with a number of traditional indices of lead poisoning. These included blood and urine lead concentrations and free erythrocyte protoporphyrin, erythrocyte zinc protoporphyrin, urinary coproporphyrin and urinary delta-aminolaevulinic acid levels. There was a highly significant negative correlation between erythrocyte PN activity and blood lead concentration (-0,83; P less than 0,0001), which was greater than that for any of the other measurements. It was therefore concluded that erythrocyte PN activity is an excellent indicator of lead exposure.
...
PMID:Erythrocyte pyrimidine-5'-nucleotidase activity as a sensitive indicator of lead exposure. 298 2

We report a rapid and reproducible assay for activity of human erythrocyte pyrimidine 5'-nucleotidase and deoxypyrimidine 5'-nucleotidase. The nucleotides CMP, UMP, dUMP, dCMP or dTMP are individually incubated 30 min at 37 degrees C with erythrocyte hemolysate and 4 mM magnesium chloride in Tris, pH 7.5. Data are provided for standardization of the reaction with each substrate. Individual nucleoside products are assayed in less than 10 min by reversed-phase high-performance liquid chromatography at 280 nm with 0-14% methanol in 0.01 M potassium dihydrogen phosphate. This is the first report of a high-performance liquid chromatographic assay system which allows quantitation of the activity of pyrimidine 5'-nucleotidase isozymes using five individual pyrimidine and deoxypyrimidine nucleotides as the substrates.
...
PMID:Assay of human erythrocyte pyrimidine and deoxypyrimidine 5'-nucleotidase by isocratic reversed-phase high-performance liquid chromatography. 298 6

The human erythrocyte generates high-energy adenosine triphosphate by anaerobic glycolysis and cycles oxidized and reduced nicotinamide adenine dinucleotide phosphate by the aerobic pentose phosphate shunt pathway. Certain enzymopathies of the pentose phosphate shunt are associated with hemolysis resulting from oxidative denaturation of hemoglobin. Glucose-6-phosphate dehydrogenase deficiency, an X-chromosome-linked disorder, is the prototype of these diseases and is genetically and clinically polymorphic. Six enzymopathies of anaerobic glycolysis cause hemolytic anemia; lactate dehydrogenase deficiency does not. In 2,3-diphosphoglycerate mutase deficiency, 2,3-diphosphoglycerate is greatly reduced and asymptomatic polycythemia is noted. Pyrimidine-5'-nucleotidase deficiency, an enzymopathy of nucleotide metabolism, is characterized by intracellular accumulations of pyrimidine-containing nucleotides, marked basophilic stippling on the stained blood film, splenomegaly, and hemolysis. Lead inhibits the nucleotidase and an identical syndrome occurs during severe lead poisoning. Hemolysis also accompanies an unusual enzymopathy characterized by a 40- to 70-fold increase (not decrease) in adenosine deaminase activity.
...
PMID:Hemolytic anemias and erythrocyte enzymopathies. 299 Feb 76


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---