Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.4.1 (phosphodiesterase)
 18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Highly sensitive technique are described for the assay of plasma membrane (5'-nucleotidase, alkaline phosphatase), microsomal (neutral alpha-glucosidase, leucyl-2-naphthylamidase) and biliary canalicular (gamma-glutamyltransferase) enzymes and for nine acid hydrolases (acid phosphatase, phosphodiesterase, beta-glucosidase, alpha-glucosidase, alpha-galactosidase, beta-galactosidase, alpha-mannosidase, N-acetyl-beta-glucosaminidase, beta-glucuronidase) in human liver. 2. Optimum and specific assay systems have been developed which give linear kinetics for all enzymes. 3. The range of enzyme activities in samples of human liver, obtained by closed needle biopsy, and sera have been determined.
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PMID:Enzyme activities in human liver biopsies: assay methods and activities of some lysosomal and membrane-bound enzymes in control tissue and serum. 1 4

alpha- and beta-Fibrinogenases (EC 3.4.21.5) were purified from Trimeresurus mucrosquamatus venom by the technique of recycling chromatography. Both enzymes were single polypeptide chains and homogeneous as judged by sodium dodecyl sulfate (SDS) polyacrylamide gel electrophoresis and ultracentrifugation. The sedimentation constants of alpha- and beta-fibrinogenases were 2.52 and 3.04 respectively. The molecular weight of alpha-fibrinogenase was 21 500--23 400, and that of beta-fibrinogenase was 25 000--26 000. The contents of proline, glycine and tryptophan were higher in beta-fibrinogenase than in alpha-fibrinogenase. The isoelectric points of alpha- and beta-fibrinogenases were pH 8.1 and 5.7 respectively. The optimal pH of alpha-fibrinogenase was about 7.4 and that of beta-fibrinogenase was around 8.5. The activity of alpha-fibrinogenase was completely destroyed after 30 min at 60 degrees C, pH 5.6, 7.4 and 9.0, while that of beta-fibrinogenase was not significantly affected by the same treatment. Both enzymes showed proteolytic activities toward fibrinogen and casein, but were devoid of phospholipase A, alkaline phosphomonoesterase and phosphodiesterase activities of the crude venom. The tosyl-L-arginine methylester esterase activity of beta-fibrinogenase was about 17 times that of the crude venom, while alpha-fibrinogenase was completely devoid of this activity. The fibrinogenolytic activity of alpha-fibrinogenase was markedly inhibited by EDTA and cysteine, while that of beta-fibrinogenase was inhibited markedly by phenylmethane sulfonylfluoride and slightly by tosyl-L-lysine chloromethylketone and cysteine.
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PMID:Physicochemical properties of alpha- and beta-fibrinogenases of Trimeresurus mucrosquamatus venom. 1 16

Beta-Adrenoceptor tachyphylaxis was induced by incubating spirally cut guinea pig tracheas with isoproterenol (2.4 x 10(-7) M) for 20 min. This incubation reduced the relaxant effects of catecholamines but not of dibutyryl cyclic AMP, theophylline or sodium nitrite. Tracheas incubated with norepinephrine, phosphodiesterase inhibitors or cyclic nucleotides became tachyphylactic to isoproterenol. Pretreatment with indomethacin prevented induction of tachyphylaxis. Incubation with adenosine, methoxamine or sodium nitrite did not induce beta-adrenoceptor tachyphylaxis. When we gave isoproterenol intramuscularly to guinea pigs, airway sensitivity to aerosolized histamine was unchanged but the toxicity of parenterally administered histamine was increased. A prolonged treatment with isoproterenol reduced airway sensitivity to histamine aerosols; this reduced sensitivity was reversed by indomethacin. Thus, beta-adrenoceptor tachyphylaxis may not explain increased toxicity of parenteral histamine after isoproterenol treatment. Elevated levels of cyclic AMP and an increased synthesis of prostaglandins may result in diminished response to beta-receptor stimulation.
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PMID:Tachyphylaxis to beta-adrenoceptor agonists in guinea pig airway smooth muscle in vivo and in vitro. 1 46

Ribonuclease activity has been extracted from adult guinea-pig epidermis by sequential homogenization in dilute sodium acetate and sulfuric acid. The extracts were subjected to ammonium sulfate fractionation and to affinity and ion exchange chromatography. Three ribonucleases (I, II, III) were separated from the sodium acetate extract and 6(A, B1, B2, B3, C, D) were isolated from the sulfuric acid extract. The degree of purification varies from 65-fold to 8,700-fold and the apparent molecular weights of the active forms of 8 of the 9 ribonucleases range from 10,000 to 36,500. No phosphodiesterase activity is present in any of the 9 fractions, but there is alkaline phosphatase activity in one (I) and deoxyribonuclease activity in a second (B3). Two of the ribonucleases have acid pH optima (a1, B3), while the others are most active between PHs 6.8 and 7.8. The activity of 4 of the fractions is sensitive to added EDTA (III, A, B2, B3,), but no stimulatory metal ions were found. Low concentrations of the polyamine spermidine enhanced the activity of 3-fractions (III, C, D). Yeast ribonucleic acid is degraded exonucleolytically by 2 fractions (I, A) and endonucleolytically by the remaining 7. In experiments with homopolyribonucleotide substrates, poly U was generally the preferred substrate. Substantial hydrolysis of poly A occurred with 2 fractions (A, B3) and slight hydrolysis of poly G with 2 other fractions (B2, C).
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PMID:Epidermal nucleases. II. The multiplicity of ribonucleases in guinea-pig epidermis. 1 63

Modern data on the nature, properties and pathways of regulation enzymes, participated metabolism of cyclic, adenosine-3',5'-monophosphate, are described. Much consideration is being given to the problem of regulation of the phosphodiesterase activity due to the effect of Ca2+-binding proteins.
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PMID:[Adenyl cyclase and adenosine-3',5'-monophosphate phosphodiesteraze: their nature, properties and regulation]. 1 91

In chick embryo cells (CEC) and plasma membranes (PM) isolated therefrom, three forms of 3',5'-cyclic adenosine monophosphate (cAMP) phosphodiesterase (PDE) were demonstrated: (1) PDE activated only by Ca2+ (Ca-PDE); (2) PDE activated only by Mg2+ (Mg-PDE); and (3) PDE stimulated in the presence of 2 mM Mg2+ by low concentrations of Ca2+ (Ca-Mg-PDE). Purified influenza A virus, under suitable conditions, lowered the activities of these PDEs. The decrease was greater in samples incubated in the presence of adenosine triphosphate (ATP) than in those incubated in its absence.
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PMID:Interaction of plasma membranes with influenza virus. VII. Effect on 3',5'-cyclic adenosine monophosphate phosphodiesterase activity. 1 92

A DNA endonuclease has been purified from eggs of Asterias forbesi by a simple four-step-purification procedure. The purified enzyme is at least 96% pure and is free of phosphatase, phosphodiesterase, and RNase. It has a pH optimum of 6.5 and does not require divalent cations. The enzyme produces 3'-phosphoryl and 5'-hydroxyl end groups. The products of exhaustive hydrolysis can be grouped in two fractions. The first fraction, 40%, contains a small amount of mononucleotides and di-, tri-, tetra-, penta-, and hexanucleo-tides. The second fraction, 60%, contains oligonucleotides larger than hexanucleotides.
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PMID:Purification and properties of a 3'-phosphoryl former endodeoxyribonuclease from eggs of Asterias forbesi. 1 46

On the basis of the information presented in this review, it is difficult to reach any firm decision regarding the role of cyclic AMP (or cyclic GMP) in synaptic transmission in the brain. While it is clear that cyclic nucleotide levels can be altered by the exposure of neural tissues to various neurotransmitters, it would be premature to claim that these nucleotides are, or are not, essential to the transmission process in the pre-or post-synaptic components of the synapse. In future experiments with cyclic AMP it will be necessary to consider more critically whether the extracellularly applied nucleotide merely provides a source of adenosine and is thus activating an extracellularly located adenosine receptor, or whether it is actually reaching the hypothetical sites at which it might act as a second messenger. The application of cyclic AMP by intrcellular injection techniques should minimize this particular problem, although possibly at the expense of new diffulties. Prio blockade of the adenosine receptor with agents such as theophylline or adenine xylofuranoside may also assist in the categorization of responses to extracellularly applied cyclic AMP as being a result either of activation of the adenosine receptor or of some other mechanism. Utimately, the developement of highly specific inhibitor for adenylate cyclase should provide a firm basis from which to draw conclusions about the role of cyclic AMP in synaptic transmission. Similar considerations apply to the action of cyclic GMP and the role of its synthesizing enzyme, guanylate cyclase. The use of phosphodiesterase inhibitors in studies on cyclic nucleotides must also be approached with caution. The diverse actions of many of these compounds, which include calcium mobilization and block of adenosine uptake, could account for many of the results that have been reported in the literature.
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PMID:The role of cyclic nucleotides in the CNS. 1 46

The effects of adrenergic and cholinergic agents as well as the effects of disodium cromoglycate (DSCG) on the levels of cyclic AMP and cyclic GMP in mouse lung fragments were studied. Levels of cyclic AMP were enhanced by two of the known beta-adrenergic agonists, epinephrine and isoproterenol. This increase was abolished by propanolol, a recognized beta-adrenergic antagonist. Disodium cromoglycate, a proposed inhibitor of phosphodiesterases, alone caused a slight, significant increase in cyclic AMP. However, in the presence of epinephrine, levels of cyclic AMP were potentiated by DSCG. DSCG behaves, therefore, as a typical cyclic AMP phosphodiesterase inhibitor. Cyclic GMP levels were increased by carbachol, acetylcholine, and the phosphodiesterase inhibitor, aminophylline, but not by DSCG, or beta-adrenergic agonists.
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PMID:Regulation of intracellular cyclic GMP and cyclic AMP levels in mouse lung fragments by disodium cromoglycate, beta-adrenergic agonists, cholinergic activators, and histamine. 1 25

The levels of cyclic adenosine monophosphate (cAMP) and two forms of cAMP phosphodiesterase with low (PDE1) and high (PDE2) affinity for the substrate were determined in homogenates from mouse liver and transplanted hepatoma 22. The level of cAMP in the tumour is 3 times lower than that in liver. By te kinetic parameters (Vmax, Km, pH optimum) adenylate cyclase from tumour does not show any significant differences as compared to the liver enzyme; the enzyme from hepatoma is, however, more sensitive to activation by F- ions. The activities of adenylate cyclase in liver and tumour cells are the same. Phosphodiesterases of cAMP from tumour and liver cells are similar in their Km values (3,3-10(-4) M for PDE1 and 2-10(-6) M for PDE2); however, the maximal and real rates of cAMP hydrolysis in hepatoma are much higher than in liver. The fact that both cAMP phosphodiesterase activities have similar dependence on Mg2+ and Ca2+ concentrations, suggests that PDE1 is a latent form of PDE2. In tumour cells the equilibrium between these two forms is probably shifted towards the enzyme with high affinity for the substrate. The results suggest that a decreased cAMP level in hepatoma cells (as compared to the liver) is due to the activation of PDE2.
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PMID:[Some features of cyclic adenosine monophosphate metabolism in mouse liver and hepatoma 22]. 2 Jan 68


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