Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.4.2.7 (adenine phosphoribosyltransferase)
 692 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The erythrocyte adenosine deaminase, nucleoside phosphorylase, hypoxanthineguanine phosphoribosyltransferase and adenine phosphoribosyltransferase activities and plasma urate concentrations were measured in 20 cases of Down's syndrome and in 20 age- and sex-matched control subjects. The mean erythrocyte adenosine deaminase and adenine phosphoribosyltransferase activities and plasma urate concentrations were significantly higher in Down's syndrome subjects than in controls (p less than 0.001, p less than 0.01 and p less than 0.001, respectively). In all subjects studied there was a positive correlation between the erythrocyte adenosine deaminase activity and plasma urate concentration (r = 0.488, p less than 0.005). The concentrations of the erythrocyte adenine nucleotides, AMP, ADP and ATP, did not differ in Down's syndrome (n = 10) from those of control subjects (n = 10). The results suggest that the increase of plasma urate concentrations is a consequence of the increase in adenosine deaminase activity in Down's syndrome patients.
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PMID:Erythrocyte adenosine deaminase, purine nucleoside phosphorylase and phosphoribosyltransferase activity in patients with Down's syndrome. 621 25

A methodology is presented for systemic analysis of purine enzymes in small lymphocyte subfractions. For the determination of 7 different enzymes of purine metabolism *hypoxanthine-guanine phosphoribosyltransferase (HG-PRT), adenine phosphoribosyltransferase (A-PRT), adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), adenosine kinase (AK), 5'-nucleotidase (5'N), and AMP-deaminase) less than 200,000 peripheral blood lymphocytes are needed. 1000-6000 lyophilised lymphocytes are incubated in micro-incubation vessels (3 microliter) with radioactive substrates for 15-180 min. Separation of substrates and products is achieved by thin-layer chromatography on PEI-cellulose. Addition of BSA to the incubation mixtures results in higher specific enzyme activities and narrower ranges of mean values of a control group.
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PMID:Enzymes of purine nucleotide metabolism in human lymphocytes. 625 89

A mathematical model of energy metabolism of human red cells is presented, which includes besides the glycolytic reactions the adenine nucleotide metabolism. The model is based on the network of chemical reactions, the thermodynamic equilibrium constants of fast reversible reactions and on the kinetic equations for irreversible enzyme reactions. The model consists of a system of 16 differential equations and allows the mathematical evaluation of metabolic levels in the steady state of energy metabolism corresponding to the in vivo state erythrocytes with the kinetic data for the enzymes derived from in vitro experiments. The dependence of the levels of metabolites in the steady state on the activity of some enzymes is analysed to characterize the regulatory properties of the system. The comparison of the steady state levels of the model with experimental data makes it possible to estimate values of some controversial enzyme parameters. Estimates of the kinetic parameters of the following intracellular processes are presented: 1) rate constant of AMP-phosphatase, 2) maximum rate of adenylate deaminase, 3) activity of adenine phosphoribosylpyrophosphate transferase and 4) adenosine transport through the cell membrane. The simulation of the preparatory phase before incubation of erythrocytes indicates, that the model also permits to compute the time course of changes of levels of metabolites. To solve the initial problem the stiff differential equation system is integrated numerically by an efficient program without the application of the quasi-steady-state approximation.
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PMID:[Mathematical modelling of glycolysis and adenine nucleotide metabolism of human erythrocytes. I. Reaction-kinetic statements, analysis of in vivo state and determination of starting conditions for in vitro experiments]. 628 49

We have studied purine metabolism in mononuclear and polymorphonuclear cells from uraemic patients using microradiochemical enzyme assays and high-pressure liquid chromatography. In mononuclear cell lysates the mean activities of adenosine deaminase (EC 3.5.4.4) and 5'-nucleotidase (EC 3.1.3.5) were significantly diminished. The activities of adenylate kinase (EC 2.7.4.3), purine nucleoside phosphorylase (EC 2.4.2.1), adenine phosphoribosyltransferase (EC 2.4.2.7), and hypoxanthine phosphoribosyltransferase (EC 2.4.2.8) were not significantly different in the two groups. The activities of adenosine deaminase and adenine phosphoribosyltransferase were reduced in the polymorphonuclear cell lysates. No clear differences emerged in the concentration of adenine nucleotides in the mononuclear cells. The significance of these changes, which are less marked than those in erythrocytes, is discussed with reference to the immunodeficiency associated with uraemia.
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PMID:Activities of enzymes involved in purine metabolism and some related adenine nucleotide concentrations of leucocytes in renal failure. 629 37

The activities of five clinically important enzymes of purine metabolism have been determined in lymphocytes from 62 patients with various types of solid tumors. The activity of purine nucleoside phosphorylase was increased in all patient groups studied, i.e. small cell bronchogenic carcinoma (n = 30), carcinoma of the breast (n = 17) and other tumors (n = 15), compared to cells form normal donors. Activities of adenosine deaminase, adenine phosphoribosyltransferase (APRT), hypoxanthine (guanine) phosphoribosyltransferase (HGPRT), and 5'-nucleotidase (5'-NUC) vary little from control values, except for lower levels of APRT in lymphocytes from patients with carcinoma of the breast. In patients with small cell bronchogenic carcinoma, enzyme levels were also determined in granulocytes, where increased APRT activity was found. Following cytostatic treatment of these patients, significant decreases were seen in lymphocytic HGPRT and 5'-NUC activities.
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PMID:Purine metabolizing enzymes in lymphocytes from patients with solid tumors. 632 Jun 1

Some purine metabolizing enzymes of lymphocytes and granulocytes were determined in 13 patients with cirrhosis of the liver and in a control group consisting of 18 healthy blood donors. Furthermore cytidine deaminase (EC 3, 5, 4, 5) (CRD) activity was determined in the granulocytes of these patients and in 16 controls. An increase of adenosine deaminase (EC 3, 5, 4, 4) (ADA) activity was found in granulocytes (P less than 0.01) as well as in lymphocytes (P less than 0.01) of the cirrhotic patients as compared to controls. Purine nucleoside phosphorylase (EC 2, 4, 2, 1) (PNP) activity in granulocytes and lymphocytes was identical in the two groups. In lymphocytes of cirrhotic patients decreased hypoxanthine guanine phosphoribosyltransferase (EC 2, 4, 2, 8) (HGPRT) (P less than 0.01), adenine phosphoribosyltransferase (EC 2, 4, 2, 7) (APRT) (P less than 0.02) and adenosine kinase activities (EC 2, 7, 1, 20) (AK) (P less than 0.05) were demonstrated. 5'-nucleotidase (5'-N (EC 3, 1, 3, 5) activity in lymphocytes of cirrhotic patients was slightly increased, the increase being correlated to the level of serum gamma globulin. Granulocytes from cirrhotic patients showed a decrease of CRD (P less than 0.05). The finding that ADA activity is increased in mature lymphocytes and granulocytes from cirrhotic patients argues against the possibility that increase of lymphocytes ADA activity is a consequence of malignant transformation or immaturity.
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PMID:Changes in some nucleoside metabolizing enzymes of lymphocytes and granulocytes from patients with cirrhosis of the liver. 641 76

Ecto-5'-nucleotidase is known to be diminished markedly in activated compared to control mouse macrophages. The level of three purine nucleoside metabolizing enzymes, adenosine deaminase (EC 3.5.4.4), purine nucleoside phosphorylase (EC 2.4.2.1), and adenine phosphoribosyltransferase (EC 2.4.2.7) were measured in the sonicates of different populations of mouse peritoneal macrophages. Levels of adenine phosphoribosyltransferase and purine nucleoside phosphorylase in macrophages that were elicited with sodium caseinate or activated in vivo by prior intravenous injection of Listeria monocytogenes were eight times higher than those in resident cells. Levels of adenosine deaminase also tended to increase and were two times higher in elicited cells than in resident cells. The Km of each enzyme was the same in each cell population. The findings suggest that the levels of the ecto-5'-nucleotidase and of the intracellular enzymes are coordinated.
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PMID:Metabolism of purines in macrophages. Effect of functional state of the cells. 677 33

1. Activities of the following enzymes involved in adenine and adenosine metabolism were found in cell-free extracts from Euglena gracilis: acid phosphatase (EC 3.1.3.2), 5'-methylthioadenosine phosphorylase (EC 2.4.2.-), adenine deaminase (EC 3.5.4.2), adenine phosphoribosyltransferase (EC 2.4.2.7) and adenosine kinase (EC 2.7.1.20). 2. The activities occurred both in heterotrophic and photoautotrophic cells and their levels did not change during light-induced chloroplast development. 3. Neither S-adenosylhomocysteinase (EC 3.3.1.1), 5'-methylthioadenosine nucleosidase (EC 3.2.2.9) and nucleoside phosphotransferase (EC 2.7.1.77) nor adenosine degrading enzymes: adenosine deaminase (EC 3.5.4.4), adenosine nucleosidase (EC 3.2.2.7), and purine-nucleoside (adenosine) phosphorylase (EC 2.4.2.1) were found in the Euglena extracts. 4. Comparison of the adenine and adenosine metabolism in Euglena and in other organisms is comprehensively presented. The metabolism in Euglena gracilis differs from that in higher animals and plants.
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PMID:Adenine and adenosine metabolizing enzymes in cell-free extracts from Euglena gracilis. 680 64

Two pathways of adenine utilization are only known in Escherichia coli K-12: the conversion to adenosine monophosphate by adenine phosphoribosyltransferase (apt gene) and ribosylation to adenine nucleosides by purine nucleoside phosphorylase (deoD gene). The purine auxotrophs defective in synthesis of inosine monophosphate de novo (pur) and carrying apt and deoD mutations cannot satisfy their purine requirements by exogenously supplied adenine or adenosine. We have selected spontaneously secondary-site revertants (designated adu) of pur apt deoD mutants, by plating on adenine or adenosine as the sole purine source. The adu mutations frequency was 6-10(-7). The phenotypical suppression of adenine phosphoribosyltransferase and purine nucleoside phosphorylase deficiency by adu mutations is neither the consequence of apt + or deoD + reversions nor the result of appearance in mutant cells of any activity converting adenine to adenosine monophosphate or adenosine. Adenine utilization in adu mutants is not caused by constitutive synthesis or genetic modification of the substrate specificity of adenosine deaminase (add gene). The direct deamination of adenine to give hypoxanthine in extracts of adu2 mutant has been shown. The data obtained suggest the possibility of a new adenine deaminase activity to appear in E. coli by means of single mutations.
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PMID:[Escherichia coli K-12 mutants assimilating adenine via a new metabolic pathway]. 680 33

1. We have studied purine metabolism in renal failure using high-pressure liquid chromatography to determine metabolite concentrations in erythrocytes and plasma, and microradiochemical assays of enzyme activity in erythrocytes. 2. The mean activities of some of the enzymes involved in purine metabolism were raised in renal failure. Significant elevations of adenylate kinase (EC 2.7.4.3), purine nucleoside phosphorylase (EC 2.4.2.1), hypoxanthine phosphoribosyltransferase (EC 2.4.2.8) and adenosine deaminase (EC 3.5.4.4) but not of adenine phosphoribosyltransferase (EC 2.4.2.7) and ribosephosphate pyrophosphokinase (phosphoribosylpyrophosphate synthetase; EC 2.7.6.1) activities were demonstrated. However, there was an overlap between results from patients with renal failure and normal (control) subjects. Erythrocyte phosphoribosylpyrophosphate levels were also unchanged. 3. Erythrocyte nucleotide concentrations especially those of inosine were raised in renal failure. 4. The plasma inosine was reduced in renal failure. 5. The significance of these changes is discussed.
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PMID:Effect of renal failure on erythrocyte purine nucleotide, nucleoside and base concentrations and some related enzyme activities. 729 37


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