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PubMed1979

The development and significance of transaminases and 5(1)-nucleotidase (5(1)-ribonucleotide phosphohydrolase) in chick testis.

The development of testicular glutamate oxaloacetate (GOT) and glutamate pyruvate (GPT) transaminases and of 5'-Nucleotidase was monitored in the male Nigerian fowl. The findings indicated triphasic and monophasic oscillations of GOT and GPT respectively with age. 5(1)-Nucleotidase was found to decrease with increase in the chronological age of the chicks. Furthermore, while GOT and GPT exhibited cubic and quadratic relationships respectively with age and testicular weights, 5(1)-Nucleotidase was related to both variables in a quadratic manner. The results are discussed in terms of spermatogenesis which may bear profoundly on the overall reproductive performance traits of the Nigerian cockerel.

Aging↗

PubMed1975

Characteristics of a pyrimidine-specific 5'-nucleotidase in human erythrocytes.

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.

Cations, Divalent↗

PubMed1989

[Hemolytic anemia caused by pyrimidine 5'-nucleotidase (P5N) deficiency 15 years later. Apropos of 2 new cases of hereditary deficit and another one of lead poisoning].

Congenital pyrimidin 5'nucleotidase deficiency manifests as hemolytic anemia with basophilic stippling. In lead poisoning, anemia, basophilic stippling and inhibition of erythrocyte pyrimidin 5' deficiency are also observed. In the present work, we report two cases of hemolytic anemia secondary to congenital deficiency of pyrimidin 5' nucleotidase and another case secondary to lead poisoning. Since 1974, when pyrimidin 5' nucleotidase deficiency was isolated, is known that hemolysis is related to the accumulation of pyrimidin nucleotides within the erythrocytes that behave as metabolic inhibitors. However, the precise metabolic process whose inhibition leads to the shortening of erythrocytes half life has not been elucidated yet.

5'-Nucleotidase↗

PubMed1986

Localization of 3'-nucleotidase and calcium-dependent endoribonuclease in the plasma-membrane of Trypanosoma brucei.

We have characterized a 3'-nucleotidase activity of T. brucei. The enzyme has a pH optimum of 8.7, is inactivated by chelating agents and stimulated by divalent cations. It is inhibited by Zn2+, Mn2+, pyrophosphate and the trypanocidal drug suramin for which it has a Ki of 3 microM. From cell fractionation experiments it is concluded that the enzyme is located in the plasma membrane. Alkaline 3'-endoribonuclease is also located in the plasma membrane of T. brucei and this activity shares a great number of properties with the 3'-nucleotidase activity, including its sensitivity to suramin. The possibility that both 3'-nucleotidase and endonuclease activities are catalyzed by the same enzyme cannot be excluded.

Animals↗

PubMed1979

5'-nucleotidase of B and T lymphocytes isolated from human peripheral blood.

The ecto-5'-nucleotidase activities of highly purified T and B lymphocytes from human peripheral blood have been investigated using biochemical and histochemical techniques. The enzyme activity of the purified B cells was about 3.5 times that of the T cells. Using a histochemical assay, 21--55% of the B cells stained positively for 5'-nucleotidase, but only 2--22% of the T cells were positive. These results are discussed in relation to the low 5'-nucleotidase activities found on peripheral blood lymphocytes from patients with chronic lymphatic leukaemia and some patients with primary hypogammaglobulinaemia.

Agammaglobulinemia↗

PubMed1981

[Dynamics of 5'-nucleotidase activity in the blood plasma in experimental myocardial infarct].

The authors studied in the bloodflow the appearance of the damaged external cellular membranes of the heart during the development of experimental myocardial infarction. The appearance of the external cellular membranes was judged by the activity of their specific marked 51-nucleotidase. It was established that myocardial infarction leads to increased activity of 51-nucleotidase in the blood plasma, which is retained for about 1 month. The maximum of activity of 51-nucleotidase reflects the most intensive resorption of the damaged cardiac tissue, and is seen from 3 to 7 days after the accident. During these time limits thrombotic complications are especially dangerous.

Alkaline Phosphatase↗

PubMed1981

A nucleotidase from Leishmania tropica Promastigotes: partial purification and properties.

Nucleotidase activity which had been found in various subcellular fractions of Leishmania tropica has been partially purified from the supernatant of the Triton X-100 treated pellet of the 100 000 g centrifugation of the L. tropica homogenate by CM-cellulose column chromatography, Con A-Sepharose affinity chromatography, isoelectrofocusing and column chromatography on Sephacryl S-300. The enzyme showed the characteristics of a nucleotidase (EC 3.1.3.31) with a broad substrate specificity. It was inhibited by the products of the reaction and by alpha, beta-methylene adenosine 5'diphosphate and adenosine 5'-9-thiomonophosphate. Nucleotidase activity of intact Leishmania cells and the inhibitory effect of Concanavalin A on the activity of the enzyme suggest also surface-associated properties of the enzyme.

Hydrogen-Ion Concentration↗

PubMed1978

Decrease in 5'-nucleotidase activity in malignant transformed and normal stimulated cells.

Analysis of six different cell types of normal and transformed fibroblasts grown in vitro and of four different cell types of normal and leukemic lymphocytes grown in vivo have shown a marked decrease of 3- to 30-fold in the specific activity of 5'-nucleotidase in the malignant cells as compared to their normal parental cells. The results have also indicated that a serum stimulation of untransformed or normal fibroblasts and a stimulation of normal lymphocytes by concanavalin A resulted in a significant decrease in the specific activity of 5'-nucleotidase of the stimulated cultures as compared to the resting cells. In both the malignant cells and the stimulated normal cells, the decrease in 5'-nucleotidase activity was not accompanied by a similar decrease in the specific activity of acid phosphatase, indicating a specific enzyme alteration in the surface membranes of the transformed and the normal stimulated cells.

Animals↗

PubMed1995

Serum 5'-nucleotidase and alkaline phosphatase activities after high dose chemotherapy and bone marrow transplantation in cases of malignancy in children.

After bone marrow transplantation in children, it is essential to detect secondary liver diseases and hepatotoxic effects of immunosuppressive therapy. These can be revealed by cytolytic syndromes sometimes associated with cholestasis. It is therefore important to find an early and specific cholestasis enzymatic marker. A retrospective study of the changes in levels of biological parameters has been carried out in 13 children who underwent one or more bone marrow transplantations. During the 3 months following bone marrow transplantation, all patients developed liver injury characterized by an early and very elevated 5'-nucleotidase activity (sometimes more than 40 times the upper reference limit), a moderate increase in alkaline phosphatase activity, a variable increase in alanine aminotransferase activity and inconstant changes in total bilirubin levels. These results show that cytolytic syndrome and cholestasis are often associated with increases in 5'-nucleotidase and alkaline phosphatase activities. These increases are not correlated, probably due to the influence of therapy on the synthesis and release of both enzymes in the liver. 5'-nucleotidase seems to be the best marker for the detection and follow-up of liver disease in this patient group.

5'-Nucleotidase↗

PubMed1995

Autoradiography-based cytochemical detection of ecto-ATPase, ecto-ADPase, 5'-nucleotidase, and extracellular adenosine production, employing 141Ce3+ as a capturing agent.

A method for the visualization of the ecto-nucleotidase enzyme activities present on the cell surface, employing 141Ce3+ as a capturing and labelling agent, is described. Phosphate ions precipitated at the cell surface can be detected by coating the cells with an autoradiographic emulsion, followed by light microscopical inspection of the formed silver grains. The activities of ecto-ATPase, ecto-ADPase and 5'-nucleotidase were detected by this approach in four different cell lines. Parallel biochemical measurements of the activities of the corresponding enzymes were carried out in order to validate, evaluate, and optimize the cytochemical detection. The finding that Ce3+ ions are inhibitory to ecto-ATPase provided evidence for the necessity of carefully establishing appropriate reaction conditions for the cytochemical determination of ecto-nucleotidases. The application of this method to the indirect detection of extracellular adenosine production from substrates like ATP has also been documented. It allows a cytochemical determination of adenosine formed through cascade nucleotide dephosphorylation. This newly described method is of high sensitivity and potentially of value for a variety of applications, including not only cytochemistry but also cell biology, and molecular biology studies.

5'-Nucleotidase↗

PubMed1994

Activation energy of serum 5'-nucleotidase as a marker for enzyme heterogeneity.

Using adenosine 5'-monophosphate (Arkesteijn; J. Clin. Chem. Clin. Biochem. 14 (1976) 155) and inosine 5'-monophosphate (Bertrand & Buret; Clin. Chim. Acta 119 (1982) 275) as substrates for the determination of serum 5'-nucleotidase, linear Arrhenius plots were obtained between 25 degrees C and 37 degrees C. With the latter method, in patients with hepatobiliary disease, activation energy is higher than in healthy subjects (67.8 +/- 0.8 kJ.mol-1 vs. 59.2 +/- 1.6 kJ.mol-1, p < 0.001). Neuraminidase treatment resulted in a significant reduction in the activation energy of serum 5'-nucleotidase from patients (63.6 +/- 0.6 kJ.mol-1, p < 0.001). Although the activation energy seen is also influenced by conditions other than sialic acid content, the results obtained are in accordance with the hypothesis that in liver disease serum 5'-nucleotidase becomes more sialylated.

5'-Nucleotidase↗

PubMed1975

Histoenzymological mapping of acid phosphatase and 5-nucleotidase in the diencephalic and mesencephalic centers of Uromastix hardwickii.

The study deals with the histoenzymological mapping of acid phosphatase and 5-nucleotidase in the various nuclei of diencephalon and mesencephalon of Uromastix hardwickii. Almost all the nuclei and the fiber tracts reveal positive activity, both for acid phosphatase and 5-nucleotidase, althouh the intensity of the enzymatic activity presents great variations. Acid phosphatase preparations have generally revealed moderate or mild activity. On the contrary, the 5-nucleotidase preparations demonstrate the activity of a higher order. For this enzyme beside the nuclei, the commissures and fore-brain bundles are seen equipped with very intense activity. On the other hand, the commissures and fore-brain pundles present moderate activity for acid phosphatase. An attempt has been made to discuss the significance of the distribution of the enzymes at various locales.

Acid Phosphatase↗

PubMed1993

Effect of fertilizer diammonium phosphate on liver, kidney and muscle 5'-nucleotidase activity of fresh water teleost fish Clarias batrachus.

The toxic effect of fertilizer Diammonium phosphate resulted in alterations of 5'-Nucleotidase activity of tissues--liver, kidney and muscles of fish C. batrachus at varying intervals and exposures. Alterations in 5'-Nucleotidase activity of body organs gave an idea of the toxicity caused by the fertilizer. Thus the enzyme 5'-Nucleotidase can be used to monitor the pollution in aquatic ecosystem.

5'-Nucleotidase↗

PubMed1993

Adenosine metabolism in the guinea pig heart: the role of cytosolic S-adenosyl-L-homocysteine hydrolase, 5'-nucleotidase and adenosine kinase.

This study was conducted to elucidate the role of S-adenosyl-L-homocysteine (SAH) hydrolase, 5'-nucleotidase and adenosine kinase in the production and removal of adenosine in the isolated guinea pig heart during normoxic (95% O2) and hypoxic (30% O2) perfusion. Using an adenosine kinase inhibitor (5'-amino-5'-deoxy-adenosine; 50 microM) and an adenosine deaminase inhibitor (EHNA; 5 microM) the total steady-state production rate of adenosine in the heart was estimated to be greater than 1.2 nmol.min-1 per g wet wt., during normoxia. Most (95%) of the SAH-derived adenosine is salvaged by adenosine kinase action. The rate of adenosine phosphorylation increased 3-fold when isolated hearts were perfused with hypoxic medium, suggesting that adenosine kinase is not substrate-saturated under normoxic conditions. The steady-state production of adenosine was also estimated during hypoxia (5.9 nmol-min-1 per g wet wt.) and compared with previously determined transmethylation rate during hypoxia (1.12 nmol.min-1 x g wet wt.). In an attempt to assess the in-vivo activity of cytosolic 5'-nucleotidase, the 5'-AMP pool was labelled by perfusing the isolated hearts with tricyclic nucleoside (TCN) which became phosphorylated (TCN-P). The release rate of both adenosine and TCN in the post-labelling phase was increased by hypoxic perfusion, suggesting that the increased rate of 5'-AMP hydrolysis may be due to increased availability of substrate, as well as activation of 5'-nucleotidase. Our findings suggest that during normoxic perfusion a significant amount of adenosine is derived from an apparently oxygen-independent mechanism (cellular transmethylation) whereas during hypoxic perfusion hydrolysis of adenine nucleotides to adenosine prevails.

5'-Nucleotidase↗

PubMedDate not supplied

[The effect of whole-body gamma irradiation on 5'-nucleotidase activity in the blood plasma of rats].

Alteration dynamics of 5'-nucleotidase (EC 3.1.3.5) in rat plasma was studied after whole-body gamma-irradiation. External gamma-irradiation with doses ranging from 0.5 to 11 Gy induced a transient rise of 5'-nucleotidase activity. An increase in the enzyme activity was found to be a function of dosage and post-exposure time. The moment of enzyme activity rise vs dose was represented as an exponential curve. The rise in plasma 5'-nucleotidase activity was assumed to be the result of lesions in flexible tissue (type F).

5'-Nucleotidase↗

PubMedDate not supplied

[Activity of 5'-nucleotidase from thymus and tumors upon administering bradykinin to tumor-bearing mice].

Activity of 5'-nucleotidase was inhibited in thymus tissue of tumor-bearing mice; bradykinin (1 mg/kg body weight) increased the enzymatic activity 2.0-2.2-fold. Administration of bradykinin led to inhibition of allogenic Crocker's sarcoma growth and to stimulation of syngeneic mastocytoma P-815 growth, which was inoculated into noninbred and BALB/c mice, respectively. Hence, bradykinin activated 5'-nucleotidase in Crocker's sarcoma and did not affect the enzymatic activity in tumor P-815. This suggests that activity of 5'-nucleotidase is of importance in evaluation of the thymus tissue state as well as it demonstrates the tumoral tissue sensitivity to bradykinin.

5'-Nucleotidase↗

PubMed1999

Concomitant blockade of P2X-receptors and ecto-nucleotidases by P2-receptor antagonists: functional consequences in rat vas deferens.

In order to assess the consequences of a concomitant blockade of P2X-receptors and ecto-nucleotidases, effects of 13 P2-receptor antagonists were investigated on contractions of the rat vas deferens elicited by alpha,beta-methylene ATP (alpha,beta-MeATP) and ATP and on the removal of ATP from the incubation medium by vas deferens tissue. Increasing concentrations of all antagonists reduced and finally abolished contractions elicited by alpha,beta-MeATP (3 microM), with IC50-values ranging from 1.1 to 100 microM. Pyridoxalphosphate-6-azophenyl-2',4'-disulphonate (PPADS), 6-azophenyl-4-amino-5-hydroxy-naphthalene-1,3-disulphonate (NH02), 4,4'-diisothiocyanatostilbene-2,2'-disulphonate (DIDS) and uniblue A also progressively reduced and finally abolished contractions elicited by ATP (1 mM). 8,8'-[Carbonylbis(imino-3, 1-phenylenecarbonyl-imino)]-bis-(1,3,5-naphthalenetrisulphonate ) (NF023), suramin, pyridoxalphosphate-6-azophenyl-2',5'-disulphonate (iso-PPADS), trypan blue and reactive blue 19, in contrast, caused only partial blockade, by 34-43% maximally; reactive blue 2 and reactive red 2 had no effect; and 6,6'-(1,1'-biphenyl-4,4'-diylbisazo)-bis-4-amino-5-hydroxy-naphtha lene-1,3-disulphonate (NH01) and Evans blue even enhanced the response to ATP. For antagonists causing full or partial inhibition, the IC50-values against ATP were close to those against alpha,beta-MeATP. All antagonists attenuated the removal of ATP, with IC25%-values ranging from 0.8 microM to >320 microM. The results confirm the frequent combination, in one antagonist molecule, of P2-receptor blockade and blockade of ecto-nucleotidases. This dual action underlies the effect of such compounds on contractions of the vas deferens elicited by ATP which, for certain substances (e.g., suramin, reactive blue 2), can be explained by a simple model in which the antagonist simultaneously blocks the degradation of ATP and a single contraction-mediating receptor (P2X1). Several observations, however, do not conform with this model, and the existence of multiple contraction-mediating receptors for ATP or multiple, pharmacologically distinct ecto-nucleotidases has to be considered.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed2004

Chronic treatment with lithium increases the ecto-nucleotidase activities in rat hippocampal synatosomes.

Lithium is a mood-stabilizing treatment used in bipolar and other psychiatric disorders. The molecular mechanisms underlying lithium action remain poorly understood. Adenosine is a neuromodulator that possesses anticonvulsant and neuroprotective properties and the ecto-nucleotidase pathway is a metabolic source of the extracellular adenosine. Here we investigated the effect of lithium on the ecto-nucleotidase pathway in synaptosomes from hippocampus and cerebral cortex of adult rats. Male Wistar rats received standard rat chow with lithium chloride (2.5 mg/g of chow) and NaCl (17 mg/g of chow) during 4 weeks. The serum lithium levels were 1.18 +/- 0.05 mEq./L. ATP and AMP hydrolysis was significantly increased (20 and 35%, respectively) in hippocampal synaptosomes of rats chronically treated with lithium chloride. No significant differences were observed in the hydrolysis of the three nucleotides by cortical synaptosomes. In conclusion, the modulation of the ecto-nucleotidase pathway may be a new explanation for the potential neuroprotective lithium action in hippocampal lesions.

Adenine Nucleotides↗