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)

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.
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PMID:Substrate specificity and pH sensitivity of deoxyribonucleotidase and pyrimidine nucleotidase activities in human hemolysates. 282 57

1. We performed an enzymatic characterization of two different fractionation procedures of ventricles from rat hearts. The enzymatic assays covered succinic dehydrogenase as a marker for inner mitochondrial membranes, monoamine oxidase as a marker for outer mitochondrial membranes, NADPH-cytochrome c reductase and RNA as endoplasmatic reticular markers, acid phosphatase as a lysosomal marker, and lactic dehydrogenase as a marker for the "soluble" compartment; DNA was estimated for nuclear contamination. 2. The plasma membrane markers 5'-nucleotidase, Ca2+-ATPase, Mg2+-ATPase, Na+-K+-ATPase, and adenylate cyclase were determined. 3. The roughly prepared membrane fractions showed increased yields of the membrane markers; the number of beta receptors, determined with (-)-[3H] dihydroalprenolol and DL-propranolol, amounted to 68 +/- 6 fmol/mg protein (KD = 3390 +/- 450 pmol, Hill coefficient = 1.5). 4. The membrane fraction prepared with a linear sucrose gradient showed an increased inner mitochondrial membrane marker; presumably the outer mitochondrial membrane was stripped off. The beta-receptor number was 39 +/- 3 fmol/mg protein (KD = 6250 +/- 300 pmol; Hill coefficient = 1.2).
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PMID:Beta-adrenergic receptors and enzymes in rat myocardial membranes: implications of fractionation procedures and beta-adrenoceptor antagonists. 284 52

The binding of 125I-bovine thyrotropin to thyroid particulate fractions from sham-operated (control) and hemithyroidectomized rats was compared to determine if a change in either the number of bovine thyroid-stimulating hormone (bTSH) binding sites or their affinity for bTSH occurs in physiological situations that evoke changes in the intensity of thyroid stimulation. Following hemithyroidectomy serum TSH levels increase and the remnant thyroid lobe enlarges. Because of compensatory thyroid hypertrophy the concentration of TSH binding sites in the thyroid glands from hemithyroidectomized and control rats was related to particulate protein concentration, to the degree of thyroid cellularity as indicated by DNA concentration, and to the concentration of the plasma membrane markers, 5'-nucleotidase and magnesium-dependent ATPase. In each of four experiments, saturation studies revealed that the maximum specific binding of TSH per unit particulate protein and per thyroid lobe was greater in particulates from remnant than from control thyroid lobes. When related to DNA concentration, the concentration of TSH binding sites in remnant lobes was approximately twice that in control lobes. Because of an increase in plasma membrane markers per lobe after hemithyroidectomy, however, there was no difference in the number of TSH binding sites when related to the concentrations of the membrane marker enzymes in the particulate fractions. As judged from Scatchard analysis, the affinity of TSH binding was lower in remnant than in control lobes. This was partially but not completely due to the increased concentration of particulate protein in the remnant thyroid. These experiments demonstrate that the increase in serum TSH levels after hemithyroidectomy in the rat is associated with alterations in TSH receptor capacity and affinity.
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PMID:Binding of bovine thyrotropin to specific sites in thyroid tissue from control and hemithyroidectomized rats. 299 11

The DNA sequence of the ushA gene, encoding UDP-sugar hydrolase (5'-nucleotidase), has been determined. The amino-terminal sequence encodes a signal peptide whose predicted processing site is confirmed by N-terminal amino acid analysis of purified mature UshA protein. The signal sequence contains a concentration of rare codons in comparison with the mature sequence. The origins of transcription from the ushA promoter have been determined, using primer extension. Three transcripts, originating within a 6 bp region, were identified and might be related to three overlapping potential -10 hexamers in the ushA promoter region. There was a discernable change in the relative proportion of these transcripts during growth-phase regulation of the ushA gene.
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PMID:Nucleotide sequence and transcriptional analysis of the E. coli ushA gene, encoding periplasmic UDP-sugar hydrolase (5'-nucleotidase): regulation of the ushA gene, and the signal sequence of its encoded protein product. 301 67

A purified preparation of macrophage colony-stimulating factor (M-CSF) free of interferon and endotoxin activity was studied for its effects on resident murine peritoneal macrophages. M-CSF was found to induce profound morphologic alterations in resident macrophages. These changes included a marked increase in cell size, membrane ruffling, and cytoplasmic vacuolization. Further, after 72 hr of incubation with 1000 U/ml of M-CSF, there were significant increases in macrophage DNA synthesis as measured by autoradiography (P less than 0.001), and in macrophage monolayer protein content (P less than 0.01). None of these changes was seen in control macrophages or those exposed to recombinant interferon-gamma (IFN). Low activity levels of the ectoenzymes 5'-nucleotidase (5'NTD) and alkaline phosphodiesterase I (APD) have been associated with certain macrophage functions, particularly the expression of tumor cytotoxicity. Macrophage monolayers exposed to M-CSF demonstrated an unaltered level of 5'NTD activity from controls and a significantly increased level of APD activity (P less than 0.01) and did not demonstrate an increased ability to kill tumor cells, as measured by the 51Cr-release assay. On the other hand, IFN caused significant decreases in both 5'NTD (P less than 0.05) and APD (P less than 0.01) and also induced marked tumoricidal activity in macrophage monolayers. These results indicate that purified M-CSF induces highly specific alterations in the functional activity and morphologic appearance of resident macrophages and these changes are distinct from those induced by IFN.
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PMID:Stimulatory effects of purified macrophage colony-stimulating factor on murine resident peritoneal macrophages. 301 77

Changes in a range of plasma membrane enzyme activities during the early period of liver regeneration are thought to be related to the initiation of DNA synthesis and the triggering of cellular activation. The sinusoidal plasma membrane was isolated from control and partially hepatectomized animals at various intervals during the pre-replicative phase. The specific activities of 5'-nucleotidase, (Na+ + K+)-ATPase, Ca2+-ATPase, Mg2+-ATPase showed that after partial hepatectomy changes in the enzyme activities at the sinusoidal plasma membrane region occur. These changes are probably related to the remodeling of the cell-surface that occurs before the division of hepatocytes.
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PMID:Changes in sinusoidal plasma membrane enzyme activities during the pre-replicative phase of liver regeneration. 301 5

Activities of key enzymes of purine metabolism [adenosine deaminase (AD); purine nucleoside phosphorylase (PNP); 5'-nucleotidase] were studied; changes in DNA content, nucleus ploidity in thymocytes, T- and B-lymphocytes in the C3HA mouse spleen during solid 22 hepatoma growth and after the immunization were monitored. Immunological properties of lymphocytes were also investigated measuring antibody formation and the reaction of blasttransformation in response to phytohemagglutinin, concanavalin A and lipopolysaccharide. Within the first 48 hrs after the tumor implantation and immunization certain nonspecific biochemical mechanisms of lymphocytes activation (elevated AD activity, decreased activity of 5'-nucleotidase, augmented intracellular DNA levels, polyploidity) were revealed. As the solid 22 hepatoma reached the maximum growth rate specific alterations in the activities of the purine metabolism key enzymes were observed reflecting the response of thymus and spleen lymphocytes to the presence of the malignant tumor.
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PMID:[Biochemical and functional characteristics of thymus and spleen lymphocytes in C3HA mice during the growth of hepatoma 22 and after immunization with sheep erythrocytes]. 302 Jul 91

Three catabolic enzymes, 5'-nucleotidase (5'NT), adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP) and one anabolic enzyme, myokinase (MK) involved in adenine nucleotide (AN) metabolism were studied in myocardium from 4 to 105 day old rats. The specific enzyme activities (nmoles/min/mg protein) at day 4 were 35.3 for 5'NT, 28.4 for ADA, 43.3 for PNP, and 5 X 10(3) for MK. At day 7, 5'NT, activities rose to 450%; PNP and ADA 150%; and MK 120%; of the day 4 level. The activities of the three catabolic enzymes were elevated for one or two weeks then declined rapidly. By day 34, they were slightly above the adult values. MK activity displayed a different time course. It continued to increase slowly with age after the initial surge. Compared to the adult heart, the total activities of these catabolic enzymes in the one- to three-week-old heart were 30% to 220% higher. This transient elevation in AN catabolic enzyme activities may be related to active DNA synthesis and cell proliferation occurred in the rat myocardium during the same period.
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PMID:Postnatal changes in enzyme activities of rat myocardial adenine nucleotide catabolic pathway. 302 44

As a first step in studies of the molecular mechanism(s) underlying gentamicin toxicity, rat kidney cortex has been subfractionated using differential centrifugation. An analytical, rather than preparative approach was used. DNA was used as a marker for the nuclei, cytochrome oxidase for mitochondria, acid phosphatase for lysosomes, catalase for peroxisomes, NADPH-cytochrome c reductase for the endoplasmic reticulum, p-nitrophenyl-alpha-mannosidase (at pH 5.5) for the Golgi apparatus, AMPase for the plasma membrane in general, and alkaline phosphatase for the brush border, and lactate dehydrogenase for the cytosol. In addition, electron microscopy was performed on the subfractions obtained. The distributions of subcellular markers obtained here for the rat kidney cortex closely resemble the corresponding distributions reported for rat liver. This procedure can now be used to look for biochemical and/or toxic changes which might be reflected in an altered distribution pattern for marker enzymes.
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PMID:Biochemical effects of gentamicin on rat kidney cortex. I. Analytical subfractionation of control tissue. 303 Jul 99

As a first step in studies on the molecular mechanism(s) underlying gentamicin toxicity, the effect of treating rats with this aminoglycoside antibiotic (100 mg/kg once or twice daily for 3 days) on the analytical subfractionation of the kidney cortex has been examined. DNA was used as a marker for the nuclei, cytochrome oxidase for mitochondria, acid phosphatase for lysosomes, catalase for peroxisomes (with reservations; see the companion paper), NADPH-cytochrome c reductase for the endoplasmic reticulum, p-nitrophenyl-alpha-mannosidase (at pH 5.5) for the Golgi apparatus, AMPase for the plasma membrane in general and alkaline phosphatase for the brush border, and lactate dehydrogenase for the cytosol. In addition, the presumptive lysosomal hydrolases N-acetyl-beta-D-glucosaminidase, p-nitrophenyl-alpha-mannosidase (at pH 4.5), cathepsin D, and DNase II were monitored. Electron microscopy was also performed on the subfractions obtained. The only significant biochemical changes brought about by gentamicin treatment were that N-acetyl-beta-D-glucosaminidase demonstrated both a greater total activity and a larger enrichment in the 104,000gav pellet, while p-nitrophenyl-alpha-mannosidase at pH 4.5 demonstrated the same total activity and a greater enrichment in the 104,000gav pellet. Since myeloid bodies were shown by electron microscopy to sediment primarily with the 500gav and 10,000gav pellets, the biochemical changes seen cannot be associated with these morphological structures. These findings suggest that selective changes in a certain subpopulation(s) of lysosomes or in certain lysosomal enzymes may be involved in the early stages of gentamicin toxicity. On the other hand, no lysosomal membrane damage was observed here, since both the latency of acid phosphatase and the recovery of this activity in the soluble cytosol were unchanged. The present investigation may also have relevance for the dosage and duration of gentamicin treatment chosen in clinical situations.
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PMID:Biochemical effects of gentamicin on rat kidney cortex. II. Analytical subfractionation after short-term, high-dose treatment. 303 Aug


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