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

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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)

It has been established that N-acetylglucosaminyl-N-acetylmuramyl-L-alanyl-D-isoglutamine (GMDP), a new synthetic analog of muramyl dipeptide, while incubated in vitro with macrophages essentially inhibits 5'-nucleotidase (5-N) activity without any influence on the activity of adenosine deaminase in these cells. The maximal effect was recorded 24 h after co-incubation. As 0.01 = 1 microgram/ml concentration of GMDP was added, the enzyme activity gradually decreased to minimum. L-D-isomer of GMDP was shown to affect 5-N activity whereas the effect of its analog with a double peptide chain GM (DP)2 was found to be less. Inhibition of 5-N activity may be one of the mechanisms by which macrophages are activated under the influence of GMDP.
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PMID:[Changes in purine metabolism in the macrophages of mice exposed to a new synthetic analog of muramyl dipeptide]. 299 Jun 3

A microassay requiring as few as 2 X 10(5) cells per assay was developed for systematic analysis of 9 purine enzymes in lymphocytes from equine peripheral blood, spleen, lymph node, thymus and bone marrow. The activities of adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), adenosine kinase (AK), deoxyadenosine kinase (dAK), deoxycytidine kinase (dCK), 5'-nucleotidase (5'-N), AMP deaminase, hypoxanthine-guanine phosphoribosyl transferase (HGPRT or HPRT), and adenine phosphoribosyl transferase (APRT) were measured by this microassay in lymphocytes from peripheral blood from four different breeds of horses (Arabian, Quarter Horse, Thoroughbred and Shetland Pony). There were no significant differences in the enzyme activities among the various breeds. Peripheral blood lymphocytes (PBL) from foals exhibited enzyme activities similar to those observed for adult animals. All lymphoid tissue contained similar levels of activity for each kinase (AK, dAK and dCK). Spleen had the highest activity for ADA, PNP, 5'-N, and HGPRT. The lowest activity for ADA, APRT, PNP and AMP deaminase was found in thymus. Enzymatic activities that varied the most among the tissue were 5'-N, ADA, APRT, HGPRT and AMP deaminase.
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PMID:Distribution of enzymes of purine metabolism in lymphocytes of horse, Equus caballus. 299 Aug 11

In slices of hippocampus from the rabbit, preincubated with [3H]noradrenaline and then continuously superfused, the modulation of the release of noradrenaline by adenosine receptors was studied. Electrical field stimulation of the slices elicited a release of [3H]noradrenaline which was inhibited in a concentration-dependent manner by various adenosine receptor agonists. From the order of potency: cyclohexyladenosine greater than (-)phenylisopropyladenosine [(-)PIA] greater than 5'-N-ethylcarboxamide-adenosine (NECA) greater than 2-chloro-adenosine greater than adenosine (+)phenylisopropyladenosine greater than ATP, the inhibitory adenosine receptor was classified as A1- (Ri-) receptor. The effect of the agonist was strongly reduced by adenosine receptor antagonists, the methylxanthines. A role for endogenous adenosine in the modulation of hippocampal noradrenaline release is supported by these findings: (1) that blockade of adenosine receptors by methylxanthines, especially by 8-phenyltheophylline, increased, whereas (2) inhibition of the uptake of adenosine decreased the evoked release of noradrenaline and (3) that deamination of endogenous extracellular adenosine by addition of adenosine deaminase to the medium enhanced the evoked transmitter release. Inhibitors of endogenous adenosine deaminase and 5'-nucleotidase were without effect. It is concluded that release of noradrenaline in the hippocampus is inhibited at the level of the noradrenergic nerve terminals by endogenous adenosine via A1 (or Ri) receptors.
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PMID:Adenosine: an endogenous modulator of hippocampal noradrenaline release. 299 2

Activities of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) as well as their ratio in chronic lymphocytic leukemia (CLL) were found to be several times lower as compared with normal cells and to depend upon the duration and severity of leukemic process. Ratio of ADA and PNP activities in CLL was inverted as compared with those of normal cells; 5'-nucleotidase activity varied within all the stages of the disease from zero values to supernormals. There was a correlation between beneficial effects of treatment of the CLL patients and an increase in ADA and PNP activities in their peripheral lymphocytes.
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PMID:[Enzymes of purine nucleotide catabolism in lymphocytes in normal states and in chronic lymphoid leukemia]. 299 63

Several B lymphoblastic cell lines are known to be relatively resistant to the combination of 2'-deoxyadenosine with an adenosine deaminase inhibitor. These cell lines are believed to have a greater capacity to dephosphorylate 2'-deoxyadenosine nucleotides, thus preventing excessive accumulation of potentially toxic metabolites. In this study, the 2'-deoxynucleoside 5'-monophosphate dephosphorylating activities of human peripheral lymphocytes were examined. Peripheral lymphocytes have at least three nucleotide 5'-monophosphate nucleotidases distinguished by different pH optimums, substrate preference, Mg2+ requirement, inhibitors, and molecular weights. Two of the enzymes appeared to be cytosolic, only one of which had significant substrate activity with dAMP. This enzyme had an acidic pH optimum (5.0), no Mg2+ requirement, was inhibited by tartrate, and demonstrated broad substrate specificity. The other cytosolic nucleotidase required Mg2+, had a pH optimum of 5.5 to 6.0, was activated by 2'-deoxyinosine, and demonstrated a substrate preference for 3'- and 5'-monophosphate 2'-deoxynucleosides of hypoxanthine, guanine, uracil, and thymine. The third enzyme, ecto 5'-nucleotidase, is associated with the cell membrane. Although the ecto 5'-nucleotidase activity was higher in the B lymphocytes, the cytosolic nucleotidases were similar in activity in the T and B lymphocytes.
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PMID:Nucleotidase activities of human peripheral lymphocytes. 299 75

The multidisciplinary approach of leukemia phenotyping, called multiple marker analysis, led to changes in the classification systems of normal hematopoiesis and leukemic cells, and introduced the use of a biological and functional definition of leukemia, rather than merely morphological-cytochemical descriptions. Two major conclusions can be drawn from the findings of multiple marker analysis: 1) differentiation of leukemia is not abnormal but blocked ("maturation arrest"), and leukemic cells retain normal maturation-linked markers; and 2) no leukemia specific marker could be detected so far. Although leukemic cells show general qualitative features in common with normal cells, some quantitative characteristics of these similar attributes are peculiar to leukemic blasts. Qualitative and quantitative enzymological characteristics help to identify the cell lineage involved and to determine the developmental point at which maturation arrest occurs. The expression of isoenzymes is often linked to the presumptive sequence of developmental stages. Subsets within ALL subtypes showed pronounced modifications in their isoenzyme patterns associated with increasing maturity. Thus, enzyme markers can provide refined definitions of subgroups by biochemical criteria. Based on recent observations using the enzyme markers TdT, adenosine deaminase, 5'-nucleotidase, purine nucleoside phosphorylase, acid phosphatase, and hexosaminidase, a scheme of enzymological expression in the various commonly accepted subtypes of acute lymphoid leukemia and acute nonlymphoid leukemia is presented. Enzyme marker analysis represents a useful tool as an adjunctive method in multiple marker analysis for assessing diagnosis, prognosis, and the evolutionary and pathogenetic mechanisms underlying the spectrum of leukemia subtypes. Furthermore, enzyme marker analysis may provide further insight into certain aspects of the pathobiology of leukemia which might not be elucidated by other methods.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Significance of enzyme markers as a part of multiple marker analysis in leukemia research. 300 Feb 10

The activity of 5'-nucleotidase, AMP deaminase, adenosine deaminase, acid phosphatase, alkaline phosphatase and nucleotide pyrophosphatase was assayed in human thyroid glands. The 5'-nucleotidase activity was higher than that of AMP deaminase which suggested that AMP undergoes degradation primarily as a result of dephosphorylation in thyroid tissue. A high acid phosphatase activity was noted as compared to that of alkaline phosphatase activity. In toxic goitre the increase in adenosine deaminase and acid phosphatase was observed together with the decrease in pyrophosphatase activity.
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PMID:Activity of 5'-nucleotidase, AMP deaminase, adenosine deaminase, acid and alkaline phosphatase and nucleotide pyrophosphatase in human thyroid. 300 51

Regulation of renal function by endogenous adenosine production was examined in isolated perfused rat kidneys. Reducing perfusate pO2 from 400 +/- 15 to 130 +/- 5 mm Hg for 20 min created an energy deficit and increased adenosine in venous perfusate (0.06 +/- 0.02 to 0.79 +/- 0.15 microM) and snap-frozen renal cortex (5.6 +/- 1.4 to 16.7 +/- 2.7 nmol/g wet wt.). A competitive inhibitor of 5'-nucleotidase, alpha,beta-methyleneadenosine diphosphate (120 microM), inhibited the production of adenosine during hypoxia (perfusate, 0.26 +/- 0.05 microM and renal cortex, 3.1 nmol/g) but did not prevent the decline in cortical tissue ATP and ADP. The inhibitor was concentrated 3-fold in renal cortex compared to perfusate and could therefore inhibit both ecto and endo 5' nucleotidases. Vascular resistance increased 11.1 +/- 0.5% during hypoxia. Inhibition of 5'-nucleotidase reduced the vasoconstrictive response by 40% (P less than .01). An A1 antagonist, 1,3-diprophyl-8-(2-amino-4-chlorophenyl)xanthine (10(-5) M), reduced the effect of hypoxia on vascular resistance by 60% (P less than .005). Adenosine deaminase (7-14 U/ml) added during hypoxia reduced venous adenosine from 1.0 to 0.3 microM and reduced vascular resistance by 3 +/- 1%. Neither the inhibitors nor adenosine deaminase significantly altered the response of glomerular filtration rate or sodium reabsorption to hypoxia. These results indicate that either ecto or endo 5'-nucleotidase controls the renal production of adenosine during an energy deficit and that endogenous adenosine constricts the renal vasculature.
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PMID:Role of 5'-nucleotidase in adenosine-mediated renal vasoconstriction during hypoxia. 300 46

We studied purine metabolism in rheumatoid arthritis (RA), adenosine deaminase (ADA), 5'-nucleotidase (5'NU) and purine nucleoside phosphorylase (PNP) activities by measuring the circulating mononuclear cells of patients with RA and healthy controls. Patients had significantly lower levels of ADA and 5'NU but not of PNP than controls. The decreases could not be related to age, antiinflammatory therapy, decreased percentages of T cells or imbalance between major T cells subsets. Differences in cell maturation or traffic could account for our observation. Alternatively, abnormalities of purine metabolism are not definitely excluded in RA if the lower enzyme activity is not sufficient to perform the metabolic steps.
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PMID:Purine enzyme levels in rheumatoid arthritis. 300 61

Activities of several adenosine metabolizing enzymes were examined in capillary preparations isolated from rabbit ventricle. Vmax and Km values for 5'-nucleotidase were 2.3 nmol/min/mg and 10 microM, respectively. For adenosine deaminase the corresponding values were 7.8 nmol/min/mg and 32 microM. S-adenosyl-homocysteine hydrolase, which forms adenosine by the hydrolysis of S-adenosylhomo-cysteine, was also present (Vmax, 0.07 nmol/min/mg; Km, 0.81 microM), as were adenosine kinase (Vmax, 0.2 nmol/min/mg; Km, 0.52 microM) and purine nucleoside phosphorylase (Vmax, 13.8 nmol/min/mg; Km, 96 microM). These enzymes were also present in microvessels (capillaries and arterioles) purified from rabbit brain. Activities of several enzymes, especially 5'-nucleotidase and adenosine deaminase, were much lower in myocytes isolated from rabbit ventricle. The study provides evidence that endothelial cells of the microvasculature from heart and brain are capable of activity forming and degrading adenosine. It is possible that adenosine formed by these cells may contribute to the local regulation of blood flow.
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PMID:Adenosine metabolism in microvessels from heart and brain. 300 95


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