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)

Human erythrocyte adenosine deaminase has been purified approximately 800,000-fold to apparent homogeneity using antibody affinity chromatography. The enzyme was shown to be a single polypeptide chain with an estimated molecular weight of approximately 38,000. The three electrophoretic forms of erythrocyte adenosine deaminase purified simultaneously by this technique were indistinguishable by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions. Several properties of the highly purified adenosine deaminase including pH optimum, Km for substrate, Ki for product, Stokes radius, sedimentation coefficient, and apparent substrate specificity were identical with the properties observed with an impure preparation of the enzyme.
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PMID:Human adenosine deaminase. Purification and subunit structure. 1 62

1. The adenosine deaminase has an approximate molecular weight of 130,000-140,000 and the composition of two polypeptide units (mol. wt about 68,000) is suggested, by means of SDS disc electrophoresis. 2. Both the alpha (Vm/Km) and beta (Vm) parameters were varied with pH and temperature. RSS (relative substrate specificity) adenosine and deoxyadenosine values for alpha and beta were 1.2 and 1.1, respectively. 3. Adenine, 2'-, 3', 5'-AMP, 5'-deoxyAMP, ADP and ATP were not deaminated by the enzyme. 4. Inhibition by Mg2+ was found in reaction with adenosine at pH 8 but not with deoxyadenosine at the same pH. Mn2+, which did not affect the reaction rate at pH 4 and 5, showed competitive inhibitory effects at pH 6, 7 and 8.
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PMID:Purification and properties of the adenosine deaminase from the midgut gland of a marine bivalved mollusc, Atrina spp. 4 29

Stimulation of cyclic AMP (cAMP) accumulation in rat cortex slices by 1 microM forskolin (F) was markedly reduced (96%) by treatment with adenosine deaminase (ADA). The effect of ADA was progressively less at higher concentrations of F, but still inhibited the response by 50% at 100 microM F. ADA-mediated inhibition of the cAMP response to 1 microM F was completely reversed by 5 microM 2-chloroadenosine (CA), an ADA-resistant analogue. Stimulation by F (controls) and F plus CA (ADA treated) in cortex slices was significantly inhibited by 200 microM caffeine (CAF) and by 10 microM 8-phenyltheophylline. cAMP accumulation in ADA-treated cortex slices stimulated with CA at concentrations from 5 to 100 microM was markedly enhanced by 1 microM F. Neither ADA treatment nor 200 microM CAF significantly affected cAMP accumulation in slices stimulated by 1 microM vasoactive intestinal polypeptide or adenylate cyclase in membranes stimulated by 1 microM F. CAF (1 mM) did not significantly increase basal cAMP levels in cortex slices, whereas 1 mM 3-isobutyl-1-methylxanthine caused a significant 80% increase and 100 microM rolipram enhanced cAMP levels by 4.5-fold. F-stimulated cAMP accumulation (1 microM) in cortex slices was inhibited 98% by 1 mM CAF and 49% by 1 mM 3-isobutyl-1-methylxanthine, and was enhanced 2.5-fold by 100 microM rolipram. These data have been interpreted to indicate that the stimulation of cAMP accumulation in rat cortex slices by 1 microM F is predominantly due to synergistic interaction with endogenous adenosine and that the inhibition of this response by CAF is largely due to blockade of adenosine receptors.
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PMID:Forskolin stimulation of cyclic AMP accumulation in rat brain cortex slices is markedly enhanced by endogenous adenosine. 130 35

Confluent monolayers of bovine pulmonary artery endothelial cells (BPAE) or human umbilical vein endothelial cells (HUVE) inhibited by 80 to 90% the production of O2- by added human neutrophils (PMNs) stimulated by plasma membrane receptor-mediated activators (formylmethionylleucylphenylalanine [fMLP], opsonized zymosan, heat-killed Staphylococci), but not by non-plasma membrane receptor-mediated activators (phorbol myristate acetate and delta-hexachlorocyclohexane). Degranulation induced by fMLP was also inhibited by BPAE. Inhibition was not affected by eicosatetraynoic acid (ETYA) or indomethacin. To assess the role of cell-cell contact, 0.45-microns-pore culture plate inserts were employed to prevent PMN-endothelial cell contact during incubation. A similar amount of inhibition of stimulated PMNs superoxide production was seen as compared to PMN-endothelial incubations where contact occurred. A soluble component released by BPAE monolayers, when added to PMNs, duplicated the inhibition seen by BPAE-PMN co-incubation. Incubation of BPAE with adenosine deaminase did not reduce inhibition of O2- production compared to controls without adenosine deaminase. There was no evidence of endothelial scavenging of O2- generated by hypoxanthine-xanthine oxidase, and inhibition of endothelial superoxide dismutase did not diminish the inhibitory effort. We conclude that cell contact is not required for BPAE inhibition of fMLP-stimulated O2- production by PMN, and that scavenging of superoxide anion is not the mechanism. The inhibitor appears to be a polypeptide with an apparent molecular weight between 1,000 and 10,000 D and does not appear to be adenosine, an arachidonate metabolite, or superoxide dismutase. The mechanism may involve down-regulation of plasma membrane receptor-mediated activation of PMNs.
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PMID:Endothelial cells inhibit receptor-mediated superoxide anion production by human polymorphonuclear leukocytes via a soluble inhibitor. 215 31

The interaction of ADP with platelets leads to shape change, exposure of fibrinogen binding sites, and aggregation, all of which have been shown to be inhibited by 5'-p-fluorosulfonylbenzoyladenosine (FSBA), an alkylating analogue of adenine nucleotides which binds covalently to a 100-kDa polypeptide in intact platelet membranes (Figures, W. R., Niewiarowski, S., Morinelli, T., Colman, R. F., and Colman, R. W. (1981) J. Biol. Chem. 256, 7789-7795). In plasma, FSBA can break down to adenosine which stimulates adenylate cyclase. To distinguish between direct effects of FSBA and the actions of adenosine, we have used washed platelet suspensions and adenosine deaminase. We studied the effects of FSBA on shape change and cyclic AMP metabolism, and on the binding of 2-methylthio-ADP, which mimics the effects of ADP on cyclic AMP metabolism at concentrations too low to activate platelets. Inhibition of ADP-induced shape change of platelets incubated with FSBA for 2 min in platelet-rich plasma was greatly reduced by adenosine deaminase. In the presence of a phosphodiesterase inhibitor, 100 microM FSBA increased platelet cyclic AMP to the same extent as did 10 microM adenosine. These effects were inhibited by theophylline, an adenosine receptor antagonist, and by adenosine deaminase. Incubation of washed platelets for 60 min with FSBA and adenosine deaminase caused a concentration-dependent inhibition of ADP-induced shape change. Inhibition closely paralleled the covalent incorporation of 3H from tritiated FSBA into platelet membranes. Under these conditions, FSBA did not block inhibition of cyclic AMP accumulation by ADP, nor did it block the binding of 2-methylthio-ADP. We conclude that part of the inhibition of shape change caused by brief exposure to FSBA is due to adenosine, but at longer times shape change is inhibited in association with covalent incorporation of sulfonylbenzoyladenosine. This effect of FSBA is independent of adenosine and occurs at a site distinct from that at which ADP inhibits adenylate cyclase.
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PMID:Two mechanisms for inhibition of ADP-induced platelet shape change by 5'-p-fluorosulfonylbenzoyladenosine. Conversion to adenosine, and covalent modification at an ADP binding site distinct from that which inhibits adenylate cyclase. 298 76

In order to discriminate between malignant and benign effusions, the values of carcinoembryonic antigen (CEA), ferritin, beta2-microglobulin (BMG), acid-soluble glycoprotein (ASP), tissue polypeptide antigen (TPA), adenosine deaminase (ADA), and immunosuppressive acidic protein (IAP) were measured in the pleural fluid of 54 patients with lung cancer, 20 with malignancies other than lung cancer, 18 with tuberculous pleurisy, and 22 with benign diseases other than tuberculosis. CEA levels in malignant effusions were significantly higher than those in benign effusions. At a cutoff level of 5 ng/ml, 68% of the patients with lung cancer and 44% of the patients with other malignancies showed elevated pleural fluid CEA levels. In 13 lung cancer cases with negative pleural fluid cytology, nine cases had elevated pleural fluid CEA levels. The mean pleural fluid BMG level of patients with benign diseases was significantly higher than that of patients with malignant diseases, but there was a marked overlap between those with malignant and benign diseases. No significant differences were found in the pleural fluid ferritin, ASP, TPA, and IAP levels between malignant and benign conditions. ASP and IAP pleural fluid levels showed significant correlations with the pleural fluid C-reactive protein (CRP) concentrations suggesting that they also reflect inflammatory activity. The mean ADA activity in tuberculous effusion was significantly higher than that resulting from other causes of pleural effusion.
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PMID:Tumor markers in pleural effusion diagnosis. 327 87

The present study confirms the previous reports that detergents can facilitate the reactivation of guanidinium chloride (GdmCl) denatured rhodanese (Tandon, S. and Horowitz, P. (1986) J. Biol. Chem. 261, 15615-15618; Tandon, S. and Horowitz, P. (1987) J. Biol. Chem. 262, 4486-4491). Here, we report the effect of the detergent, lauryl maltoside, on the reactivation of several enzymes other than rhodanese. For this study we used five different enzymes each having a single polypeptide chain, namely: adenosine deaminase; 3-phosphoglyceric phosphokinase; myokinase; 3 alpha-hydroxysteroid dehydrogenase; and phosphoglucomutase. The regain of enzyme activity was used to monitor refolding. Like rhodanese, these enzymes were denatured in 6 M GdmCl and diluted into a buffer containing various concentrations of lauryl maltoside. The effect of lauryl maltoside on reactivating these proteins depended on the specific enzyme used. For example, in the presence of lauryl maltoside, reactivation of adenosine deaminase increased to 98%, while phosphoglucomutase could not be reactivated significantly. The critical micelle concentration (CMC) of lauryl maltoside was measured under the present experimental conditions using 2-(p-toluidinyl)naphthalene 6-sulfonate (TNS) as an apolar fluorescent probe, and gave a value of 0.085 mg.ml-1 in 10 mM sodium phosphate (pH 7.4). The reactivating effect of lauryl maltoside was not generally related to its CMC. In some cases an induction period was observed before the enzyme attained its steady-state velocity. This might suggest the presence of intermediate(s) in the refolding pathway that could have been stabilized by the detergent. These findings indicate that 'non-denaturing' detergents may be useful for assisting reactivation of enzymes, although the optimum conditions will have to be determined for each individual case.
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PMID:The effects of lauryl maltoside on the reactivation of several enzymes after treatment with guanidinium chloride. 338 70

The biologic actions of vasoactive intestinal polypeptide (VIP) on insulin binding, glucose uptake and utilization, and on lipolysis were studied. At concentrations between 10(-10) and 10(-7) mol/l VIP influenced neither glucose uptake nor glucose incorporation into lipids under basal and insulin-stimulated conditions. This effect was independent of the presence of adenosine deaminase in the incubation medium. At 10(-8) mol/l VIP increased insulin binding affinity slightly but not significantly, shifting the ID-50 from 12.4 ng/ml to 10.3 ng/ml, without any change in receptor number. However, VIP showed a marked dose-dependent lipolytic activity with the lowest effective concentration at 10(-9) mol/l. At 10(-6) mol/l glycerol release increased 7.3-fold as compared to basal lipolysis. In conclusion, VIP did not affect adipose tissue metabolism at physiologic concentrations. In the rare Verner-Morrison syndrome, however, the potent lipolytic activity of VIP may contribute to the metabolic disturbances observed.
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PMID:Effect of vasoactive intestinal polypeptide (VIP) on glucose and lipid metabolism of isolated rat adipocytes. 342 Mar 1

As an aid in the differential diagnosis of exudative pleural effusions, tumor markers were investigated. We measured immunosuppressive acidic protein (IAP), carbohydrate antigen 19-9 (CA 19-9), tissue polypeptide antigen (TPA), carcinoembryonic antigen (CEA), adenosine deaminase (ADA), and alpha 1-acid glycoprotein (AGP) in the pleural fluid of 36 patients with carcinomatous pleural effusions and of 35 patients with tuberculous pleurisy because we have frequently found these diseases to be associated with exudative pleuritis. Tuberculous pleural effusions had significantly higher levels of IAP, ADA, and AGP than carcinomatous effusions (p less than 0.005). On the other hand, CEA, CA 19-9, and TPA were significantly higher in carcinomatous pleural fluids than in tuberculous fluids (p less than 0.05). There was a correlation between IAP and AGP levels, and their specificity was low. Therefore, combined assays of CEA, CA 19-9, and ADA may be useful in distinguishing pleural effusions due to malignancies from those of tuberculous origin.
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PMID:Carcinomatous and tuberculous pleural effusions. Comparison of tumor markers. 397 60

We describe a genetic polymorphism of cytosol polypeptide with mol. wt. of 38,000 detected in phytohemagglutinin (PHA)-stimulated peripheral blood lymphocytes by two-dimensional gel electrophoresis. Three different electrophoretic phenotypes (type 1-1, 2-1, 2-2) of the polypeptide have been identified in a Japanese population. Family and population studies indicate that three phenotypes are determined by two common alleles at a single autosomal locus. Since the polypeptide is mainly present in cytosol of cells, we propose that the polypeptide be temporarily designated as cytosol polypeptide with mol.wt. of 38,000 (CP38) and that the gene for CP38 be designated as CP38. The gene frequencies of two common alleles (CP38(1) and CP38(2)) are 0.899 and 0.101, respectively, in a Japanese population. The data on gel filtration of cytosol proteins on a Sephadex G-100 column suggest that CP38 exists as a dimer in the cytosol. CP38 was observed in the wide range of different cells, including B-lymphoblastoid cells, adult skin fibroblasts, HeLa cells, and erythrocytes. In 11 out of 72 individuals, the phenotypes of CP38 were different from those of adenosine deaminase which is similar to CP38 in subunit size, cell distribution, and allele frequencies. These data indicate that CP38 is a new polymorphic polypeptide encoded by an autosomal locus.
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PMID:Genetic analysis of human lymphocyte proteins by two-dimensional gel electrophoresis. VII. Genetic polymorphism of cytosol polypeptide with molecular weight of 38,000. 401


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