Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.4.4 (adenosine deaminase)
 5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pericardial tuberculosis is rare, and because of the difficulty in isolating the causative organism, the diagnosis is often missed. Adenosine deaminase, an enzyme associated with purine metabolism, shows markedly high levels of activity in tuberculous effusion. We report a case of tuberculous pericarditis diagnosed by high levels of adenosine deaminase activity, and where the pericardial fluid cultures revealed acid-fast organisms.
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PMID:A case of tuberculous pericarditis--use of adenosine deaminase activity (ADA) in early diagnosis. 222 12

Four 2-amino-6-halo- and four 6-halo-2',3'-dideoxypurine ribofuranosides (ddPs) were synthesized and tested for in vitro activity to suppress the infectivity, cytopathic effect, Gag protein expression, and DNA synthesis of human immunodeficiency virus (HIV). The comparative order of in vitro anti-HIV activity of the eight 6-halo-ddPs was as follows: 2-amino-6-fluoro, 2-amino-6-chloro, 6-fluoro greater than 2-amino-6-bromo greater than 2-amino-6-iodo, 6-chloro greater than 6-bromo greater than 6-iodo. 2-Amino-6-fluoro-, 2-amino-6-chloro-, and 6-fluoro-ddPs showed a potent activity against HIV comparable to that of 2',3'-dideoxyinosine (ddI) or 2',3'-dideoxyguanosine (ddG) and completely blocked the infectivity of HIV without affecting the growth of target cells. The lipophilicity order was as follows: 2-amino-6-iodo greater than 2-amino-6-bromo greater than 2-amino-6-chloro greater than 2-amino-6-fluoro much greater than ddG greater than ddI. All eight 6-halo-ddPs were substrates for adenosine deaminase (ADA; adenosine aminohydrolase, EC 3.5.4.4). The relative rates of hydrolysis by ADA were as follows: ddA, 2-amino-6-fluoro much greater than 2-amino-6-chloro, 2-amino-6-bromo greater than 2-amino-6-iodo. Taken together, these compounds may represent an additional class of lipophilic prodrugs for ddI and ddG and may also provide a strategy for endowing therapeutic purine nucleosides with desirable lipophilicity.
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PMID:Lipophilic halogenated congeners of 2',3'-dideoxypurine nucleosides active against human immunodeficiency virus in vitro. 225 Dec 84

Adenosine deaminase (adenosine aminohydrolase; E.C. 3.5.4.4) has been purified 4686-fold from egg yolk. The procedure developed was used to isolate the enzyme from eight chicken eggs. An easily prepared affinity column employing purine riboside was used as the final step in the purification. The method developed permits the rapid isolation and a high recovery of the protein. The specific activity of the enzyme preparation obtained is 81.4 mU/mg.
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PMID:Purification of adenosine deaminase from chicken-egg yolk by affinity column chromatography. 228 6

Recombinant retroviruses encoding human adenosine deaminase (ADA; adenosine aminohydrolase, EC 3.5.4.4) have been used to infect murine hematopoietic stem cells. In bone marrow transplant recipients reconstituted with the genetically modified cells, human ADA was detected in peripheral blood mononuclear cells of the recipients for at least 6 months after transplantation. In animals analyzed in detail 4 months after transplantation, human ADA and proviral sequences were detected in all hematopoietic lineages; in several cases, human ADA activity exceeded the endogenous activity. These studies demonstrate the feasibility of introducing a functional human ADA gene into hematopoietic stem cells and obtaining expression in multiple hematopoietic lineages long after transplantation. This approach should be helpful in designing effective gene therapies for severe combined immunodeficiency syndromes in humans.
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PMID:Expression of human adenosine deaminase in mice reconstituted with retrovirus-transduced hematopoietic stem cells. 229 99

Phosphatidylcholine secretion in type II pneumocytes has been reported to be stimulated by P1 and P2 purinoceptor agonists. P1 receptors are divided into A1 and A2 subtypes with opposite effects on the levels of adenosine 3',5'-cyclic monophosphate (cAMP). Stimulated secretion in type II cells is mediated by the A2 receptor and accompanied by an increase in cAMP concentration. We now report evidence suggesting the existence of an A1 receptor-inhibiting secretion in type II cells from adult rats. The rate of phosphatidylcholine secretion was approximately doubled by 5'(N-ethylcarboxyamido) adenosine (NECA), terbutaline, and forskolin, all of which increase cAMP levels. Adenosine deaminase increased the stimulatory effect of these agonists to approximately three-fold but it had not effect on secretion stimulated by agonists which do not increase cAMP levels. The effect of adenosine deaminase on terbutaline-stimulated secretion was antagonized by selective adenosine A1 receptor agonists, N6-cyclopentyladenosine (CPA) and 1-deaza-2-chloro-N6-cyclopentyladenosine (DCCA). The maximum inhibitory effects of CPA and DCCA were achieved at 10(-9) M and 10(-11) M, respectively. At these concentrations CPA and DCCA had no effect on the rate of basal secretion or on terbutaline-stimulated secretion in the absence of adenosine deaminase. We suggest that adenosine deaminase stimulates phosphatidylcholine secretion by removing adenosine that occupies A1 receptors, thus reversing inhibition of cAMP-mediated secretion.
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PMID:Adenosine A1 receptor-mediated inhibition of surfactant secretion in rat type II pneumocytes. 230 99

Adenosine deaminase has been localized in the plasma membrane of erythrocytes and platelets by means of immunological techniques using light and electron microscopy with cells in suspension. In erythrocytes, adenosine deaminase is associated with the external side of the plasma membrane. In platelets, the enzyme is associated with the external side of the plasma membrane, which is known to extend through the canalicular system of these cells. These results confirm our previous findings, based on biochemical studies, concerning the attachment of the enzyme to cell membranes.
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PMID:Association of adenosine deaminase with erythrocyte and platelet plasma membrane: an immunological study using light and electron microscopy. 233 24

Adenosine deaminase, a purine metabolic enzyme, was studied in lymphoid tissues of the developing chicken in order to evaluate whether enzyme activity is related to development of the immune system in birds in the same way as for mammals, in which adenosine deaminase is essential for lymphocyte differentiation, especially for the T-cell lineage. Enzyme activity was assayed in thymocytes and bursal lymphocytes at different times during chicken development ranging from the 17th day of embryonic life up to the 50th day after hatching. Adenosine deaminase activity was significantly higher in the bursa than in the thymus, regardless of whether such an activity was expressed per mg protein or per 10(8) cells; moreover, no substantial difference in the relative levels of adenosine deaminase was observed in thymocytes at the various stages of thymus development studied. Significant changes in enzyme activity, however, were found in bursal lymphocytes in which different amounts of adenosine deaminase appeared to be related to definite stages of bursal development and to specific immunological responsiveness of B lymphocytes to intravenously injected antigens. Therefore, if adenosine deaminase does play a role in the functional maturation of the immune system in birds, such a role appears to be related to the differentiation of the B- rather than the T-cell lineage.
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PMID:Questioning the role of adenosine deaminase in the development of B lymphocytes in chicken bursa. 233 59

The enzyme activities of S-adenosylhomocysteine hydrolase, adenosine deaminase and pyruvate kinase were determined in normal human erythrocytes subpopulations of different ages separated by centrifugation on a discontinuous Percoll:NaCl density gradient. The levels of S-adenosylhomocysteine hydrolase activity were found to undergo a sharp decrease with red cell ageing. Adenosine deaminase activities were, however, less critically dependent on erythrocyte age.
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PMID:S-adenosylhomocysteine hydrolase and adenosine deaminase activities in human red cell ageing. 238 22

Adenosine deaminase was estimated in ascitic fluids of 49 patients with ascites (19 tuberculous, 20 cirrhotic, and 10 malignant). The adenosine deaminase concentration in tuberculous ascitic fluid was 98.8 +/- 20.1 U/L (mean +/- SD), which was significantly more than that noted in cirrhotic (14 +/- 10.6 U/L) or malignant (14.6 +/- 6.7 U/L) ascitic fluids (p less than 0.001 for each). At a cut-off value of greater than 33 U/L, the sensitivity, specificity, positive and negative predictive value, and the overall diagnostic accuracy for diagnosing tuberculous ascites were 100%, 96.6%, 95%, 100%, and 98%, respectively. We conclude that estimation of adenosine deaminase in ascitic fluid is an easy and reliable method for diagnosing tuberculous ascites.
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PMID:Value of adenosine deaminase estimation in the diagnosis of tuberculous ascites. 238 24

Stimulation of sympathetic fibers or infusion of norepinephrine (NE) into the superior mesenteric artery (SMA) leads to an initial decrease in intestinal blood flow, which is followed by a return of flow toward the base-line value (autoregulatory escape) despite continued nerve stimulation or NE infusion. Although the mechanisms responsible for "autoregulatory escape" have not been defined, accumulation of vasodilator metabolites is frequently invoked to explain this phenomenon. Inasmuch as histamine and adenosine exist in high concentrations in the intestinal mucosa and both are potent vasodilators, we examined the effects of chlorpheniramine (an H1 blocker) and adenosine deaminase (degrades adenosine) on autoregulatory escape from NE infusion. In autoperfused piglet intestinal preparations, we measured SMA blood flow and the arteriovenous oxygen difference during intra-arterial NE infusion before and after blockade with chlorpheniramine or adenosine deaminase. Adenosine deaminase pretreatment increased the peak vasoconstrictor and reduced the steady-state escape responses to NE infusion. Chlorpheniramine did not affect either the vasoconstrictor or escape responses. The oxygen uptake changes induced by NE infusion were not dramatically modified by either treatment. These results indicate that adenosine but not histamine is responsible for at least part of the escape of intestinal blood flow from NE infusion.
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PMID:Autoregulatory escape from norepinephrine infusion: roles of adenosine and histamine. 245 33


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