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)

Using liver from nonadrenalectomized adult male rats, binding sites for [3H]dexamethasone in particulate fractions are demonstrated. The binding is thermolabile, saturable, and specific for glucocorticoid. The apparent dissociation constant (Kdapp) for [3H]dexamethasone (0.48 +/- 0.084 microM) is 60-fold greater than that for cytosolic receptor (7.9 +/- 1.5 nM). The Kdapp for [3H]cortisol in particulate fractions is 2.5-fold lower than for [3H]dexamethasone (Kdapp = 0.18 microM). The binding capacities for particulate and cytosolic glucocorticoid-binding sites also differ significantly, with particulate sites at least 9.1-fold more concentrated than cytosolic sites in liver tissue. Particulate sites are determined in Percoll density gradients to have a density of 1.039 g/cc. Saturable [3H]dexamethasone radioactivity coelutes from these gradients with the plasma membrane marker enzyme 5'-nucleotidase. Adrenalectomy causes the complete loss of particulate binding sites by 6 days postadrenalectomy; however, these sites can be regenerated to two thirds of the nonadrenalectomy level by 20-30 days postadrenalectomy.
Endocrinology 1988 Sep
PMID:[3H]dexamethasone binding to plasma membrane-enriched fractions from liver of nonadrenalectomized rats. 284 Nov 3

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.
J Biol Chem 1988 Sep 05
PMID:Growth inhibition of transformed mouse fibroblasts by adenine nucleotides occurs via generation of extracellular adenosine. 284 30

In 18 anesthetized dogs, antroduodenal and pyloric motility was monitored in vivo by a sleeve and perfused side-hole manometric assembly and by antral and duodenal serosal strain gauges. Close intra-arterial injection to the pylorus of dynorphin-(1-13) (Dyn) for kappa-receptors, [D-Pen2,5]enkephalin (DPen2,5-Enk) for delta-receptors, and [N-Me-Phe3-D-Pro4]morphiceptin (PL017) and [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin (DAGO) for mu-receptors showed no excitatory effect in the pylorus. When pyloric motor activity was increased by duodenal field stimulation 3-5 cm aboaad from the pylorus, Dyn greater than DPen2,5-Enk greater than DAGO produced a dose-dependent inhibition of the pyloric motor activity. Naloxone (200 micrograms/kg iv and 20 micrograms ia) had no effect on the pyloric excitation due to duodenal field stimulation, but it reduced the inhibitory response of intra-arterially injected opioids. In addition, opioid binding ([3H]diprenorphine) in microsomal and mitochondrial fractions from the inner circular muscle ring of the pylorus showed a distribution similar to the neuronal marker [3H]saxitoxin but no correlation to the plasma membrane marker 5'-nucleotidase. These results suggest the existence of inhibitory opioid receptors (kappa- and delta-receptors) on excitatory neurons in the intestinal neuronal pathway, which activates the canine pylorus.
Am J Physiol 1988 Sep
PMID:Inhibitory opioid receptors in canine pylorus. 284 1

Cell-surface 5'-nucleotidase was assayed by incubating intact cells with 5' [3H]AMP in iso-osmotic buffer and measuring [3H]adenosine production. The activity of cell surface 5'-nucleotidase in small resting lymphocytes and in cells of the B cell line BCL1 was 5.7 and 1.1 nmol/min/mg protein respectively at 37 degrees C. The 5'-nucleotidase was inhibited by Concanavalin A and anti-IgM, the inhibition by anti-IgM being reversible. Incubating the lymphocytes in the presence and absence of mitogens in inositol-free medium for 15 min, 60 min, and 24 h had no effect on 5'-nucleotidase activity. The reaction product adenosine as well as adenine nucleotides were shown to inhibit mitogen-induced proliferation.
Immunol Lett 1988 Sep
PMID:Role of inositol starvation on ecto-5'-nucleotidase activity during mitogen-induced lymphocyte activation. 284 80

Plasma membranes were isolated from the livers of various animal species representing the four vertebrate classes: Amphibia, Reptilia, Aves and Mammalia. These liver plasma membranes displayed comparable levels of purity as judged by marker enzyme analysis. The activities of the two marker enzymes, 5'-nucleotidase and gamma-glutamyltranspeptidase displayed striking, and quite different, species-dependent differences, with no apparent relationship to phylogeny. alpha 1 and beta-adrenergic receptors were characterized in isolated liver plasma membranes by radioligand binding techniques. The hepatic beta-adrenergic receptor was found to be expressed in all animals studied; the hepatic alpha 1-adrenergic receptor was absent in Amphibia and Reptilia, co-expressed with the beta receptor in Aves, and dominant over the beta receptor in Mammalia. These results suggest that, in liver, the beta-adrenergic receptor is more primitive while the alpha 1-adrenergic receptor is of a more recent phylogenetic origin. It is proposed that the latter may have evolved in conjunction with hepatic sympathetic innervation.
Mol Cell Biochem 1988 Sep
PMID:Hepatic alpha 1 and beta adrenergic receptors in various animal species. 285 16

Cyclic AMP has been implicated as a regulator of capacitation, but the control of its metabolism in sperm remains obscure. A recent study of mouse sperm has shown capacitation-related changes in the activities of both adenylate cyclase, which increased during incubation, and cyclic nucleotide phosphodiesterase, which decreased. The present study was conducted to extend these observations by measuring phosphodiesterase activity in sperm incubated in media with modified calcium and/or glucose content, conditions known to modulate fertilizing ability. Phosphodiesterase activity of sequential sperm samples, taken first when sperm are essentially uncapacitated and then when they are either partially or completely capacitated, decreased with time under all conditions, and in each case the greater fall in activity was seen in the medium that would support the greater change in fertilizing ability of the sperm population. Sperm washed by centrifugation to remove epididymal fluid also displayed a reduction in phosphodiesterase activity with time. The medium surrounding the sperm contained about half of the total phosphodiesterase activity, as well as 5'-nucleotidase and adenosine deaminase. The crude enzyme preparation showed complex kinetic behavior when assayed over a range of cAMP concentrations, but the reduction in activity with time was seen at all substrate levels. The observed changes in phosphodiesterase activity, together with the increased adenylate cyclase activity seen under these sperm incubation conditions, would increase cAMP availability with time, thus providing further evidence for a fundamental role for cAMP in controlling the events of capacitation.
Gamete Res 1987 Sep
PMID:Phosphodiesterase activity of mouse sperm incubated under conditions that modulate fertilizing potential in vitro. 285 27

Fractionation of rat liver by homogenization and differential centrifugation revealed that only about 83% of the transglutaminase activity in the tissue is in a soluble form, and that the remainder is associated with the particulate fraction. This latter activity remained with the membranes even after they were extensively washed to remove 99% of such soluble enzymes as lactate dehydrogenase and aldolase. Subsequent fractionation of the membranes by isopycnic density gradient centrifugation in sucrose resulted in a single band of transglutaminase activity at a density of 1.194 g/cm3. This activity was coincident with the major band of plasma membranes, which was identified by its content of 5'-nucleotidase, alkaline phosphodiesterase I, alkaline phosphatase and leucine aminopeptidase activities. After treatment with digitonin and fractionation on sucrose gradients, the transglutaminase activity and the plasma membrane marker enzyme activities were found at a new density of 1.210 g/cm3, while the enzyme markers for the other membrane fractions remained unchanged. From these data, we conclude that approximately 17% of the transglutaminase activity in rat liver is specifically associated with the plasma membranes.
Arch Biochem Biophys 1985 Sep
PMID:Subcellular localization of a membrane-associated transglutaminase activity in rat liver. 286 17

Myometrial plasma membrane (MPM) preparations from rats treated with oestradiol were obtained by discontinuous sucrose-gradient centrifugation. The preparations contained calcium-stimulated and magnesium-dependent ATPase (Ca2+/Mg2+-ATPase). A dramatic decrease in the activity of Ca2+/Mg2+-ATPase was observed when preparations were treated with 0.025-10 mumol prostaglandins E2 and F2 alpha (PGE2 and PGF2 alpha)/l. In contrast, there was a marked increase in MPM-bound 5'-nucleotidase activity at low concentrations (up to 2 mumol/l) of PGE2 and PGF2 alpha; higher concentrations (up to 10 mumol/l), however, led to a progressive inhibition of enzyme activity. Association (specific and non-specific binding) of PGE2 and PGF2 alpha with MPM at pH 7 was found to require Ca2+ (half-maximal concentration approximately 0.7 mmol/l). Changes in the allosteric properties of MPM-bound 5'-nucleotidase by concanavalin A (as reflected by changes in the Hill coefficient) indicated a fluidization of the membrane induced by PGE2 and PGF2 alpha. The steady-state fluorescence anisotropy of 1,6-diphenyl-1,3,5-hexatriene-labelled MPM decreased in PGE2- and PGF2 alpha-treated MPM from 1.24 +/- 0.04 (S.D.) to 0.66 +/- 0.01 and 0.74 +/- 0.01 respectively, which is consistent with a general increase in membrane fluidity. It is suggested that PGE2 and PGF2 alpha promote changes in the physical properties of MPM which may be relevant to the induction of uterine contractions by enzymatic regulation of intracellular calcium concentrations.
J Endocrinol 1986 Sep
PMID:Effect of prostaglandins E2 and F2 alpha on membrane calcium binding, Ca2+/Mg2+-ATPase activity and membrane fluidity in rat myometrial plasma membranes. 294 78

5'-Nucleotidase from chicken gizzard smooth muscle has been extracted, using a sulfobetaine derivate of cholic acid, and purified to homogeneity by employing three chromatographic steps. It is shown that the purification scheme can be applied to 5'-nucleotidase from other sources, such as rat liver. On sodium dodecyl sulfate polyacrylamide gels, stained with silver nitrate, the purified enzyme from chicken gizzard shows a single polypeptide band with an apparent molecular mass of 79 kDa. The enzyme purified from rat liver exhibits a molecular mass of 73 kDa in agreement with published data [Bailyes, E.M., Soos, M., Jackson, P., Newby, A. C., Siddle, K. & Luzio, J.P. (1984) Biochem. J. 221, 369-377). Gel filtration, using non-denaturating detergent solutions, indicates that the native enzyme may exist as a homodimer (152 kDa) or homotetramer (310 kDa). Antibodies raised against the enzyme purified from chicken gizzard bind only 5'-nucleotidase, solubilized from chicken muscular sources, when immobilized, but not from chicken or rat liver. The existence of tissue specific variants of 5'-nucleotidase is therefore postulated and it appears that these particular isoforms can also be classified in membranous and secretory forms of 5'-nucleotidase. They also differ in their mode of interaction with actin. The AMPase activity of the membranous (= muscular) isoform is inhibited to a considerably higher percentage by F-actin than the enzyme isolated from rat liver.
Eur J Biochem 1985 Sep 02
PMID:An improved procedure for purifying 5'-nucleotidase from various sources. Evidence for tissue and species differences in their molecular mass and affinity for F-actin. 299 65

This paper describes the isolation of plasma membrane vesicles formed by nitrogen cavitation of canine neutrophils. Plasma membranes from disrupted cells were separated from other membranes and organelles by Percoll-density gradient centrifugation. Transmission electron microscopic examination of membrane preparations chromatographed on either Sephacryl S-1000 or Sepharose 4B revealed that two populations of plasma membrane vesicles were formed: large (176 +/- 22nm), and small (119 +/- 11nm). Purified large vesicles were separated from Percoll and contaminating cytosol by Sephacryl S-1000 chromatography. Small vesicles were obtained free of Percoll by recavitating purified large vesicles. Problems encountered due to the presence of a soluble 5'-nucleotidase inhibitor also are discussed. Large and small membrane vesicles were separated into adherent and non-adherent populations by affinity chromatography on either concanavalin A-Sepharose or lentil lectin-Sepharose columns.
J Leukoc Biol 1985 Sep
PMID:Isolation of canine neutrophil plasma membranes. 299 61


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