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:3.1.4.1 (phosphodiesterase)
18,767 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two forms of cyclic nucleotide phosphodiesterase (ES 3.1.4.17)--PDE-I and PDE-II--sensitive and resistant to Ca-dependent protein regulator, were isolated from the soluble fraction of rabbit heart by chromatography on DEAE-cellulose. Both forms of enzyme are inhibited by 30--50% by Ca2+ (10(-4) M). Addition of Ca-dependent protein regulator activates PDE-I and eliminates Ca2+-induced inhibition of PDE-II. In heart extract Ca2+ increases the phosphodiesterase activity 1.5-fold. The amount of PDE-I makes up to about 10% of total phosphodiesterase activity of the heart; that of PDE-II is about 90%. In the presence of Ca-dependent protein regulator the rate of 3', 5'-AMP hydrolysis by PDE-I is increased 5--15-fold, while that of 3', 5'-GMP hydrolysis only 2.5-fold. Both PDE-I and PDE-II have close Km values for substrates--(3.5--4.0).10(-6) M for 3', 5'-AMP and 14.10(-6) M for 3', 5'-GMP. Inhibition by Ca2+ and effect of Ca-dependent protein regulator manifest themselves in changes in V for cyclic nucleotide hydrolysis and do not alter the Km value for the enzyme.
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PMID:[Separation and investigation of the regulatory properties of two forms of cyclic nucleotide phosphodiesterase from rabbit heart--sensitive and insensitive to Ca-dependent regulator protein]. 21 70

A calcium-dependent cyclic nucleotide phosphodiesterase from rat cerebrum was, in the absence of activator protein, inhibited by various monovalent cations. The inhibition was rapid, readily reversible, and concentration-dependent, with 100 mM cesium, rubidium, or potassium ion inhibiting essentially all basal enzyme activity, while 100 mM sodium or lithium ions produced only moderate inhibition. The potency of the cations in inhibiting the enzyme was Cs greater than or equal to Rb greater than K greater than Na greater than or equal to Li. Potassium ions increased the apparent Km for cyclic GMP and cyclic AMP by 3- and 5-fold, respectively. At 100 mM, the monovalent cations inhibited enzyme activated by the calcium-dependent activator by only 15 to 30%, while at 55 mM no inhibition pertained. Potassium and sodium ions at 55 mM had no effect on the calcium-independent phosphodiesterase from rat cerebrum. The results indicate that at normal intracellular concentrations of potassium ions the activity of the calcium-dependent phosphodiesterase is virtually completely dependent on the presence of calcium plus activator protein.
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PMID:Calcium-dependent 3':5'-cyclic nucleotide phosphodiesterase. Inhibition of basal activity at physiological levels of potassium ions. 21 28

1. To test the hypothesis that inhibition of cyclic nucleotide phosphodiesterase is the major mechanism of the bronchodilator action of theophylline in reversible airways disease, the effects of therapeutic plasma levels of the drug on human pulmonary phosphodiesterase activity were examined. 2. Therapeutic levels of theophylline inhibited the phosphodiesterase-catalysed hydrolysis of adenosine cyclic 3',5'-monophosphate (cAMP) and guanosine cyclic 3',5'-monophosphate (cGMP), but the percentage inhibition was relatively small. 3. The results, while supporting the assumed contribution of phosphodiesterase inhibition to the overall mechanism of theophylline action, suggest that other presently unknown factors must also be taken into consideration to fully explain the beneficial effects of theophylline in reversible airways disease.
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PMID:Inhibition of human pulmonary phosphodiesterase activity by therapeutic levels of theophylline. 21 63

1. Reactive Blue 2 (Cibacron Blue 3G-A) is a competitive inhibitor of bovine heart cyclic nucleotide phosphodiesterase (K(i) 0.3mum). The K(i) increases with increasing temperature, suggesting that hydrophobic interactions are not largely responsible for the binding of the dye. Another 25 sulphonated aromatic dyes are also competitive inhibitors of the cyclic nucleotide phosphodiesterase (K(i) values in the range of 0.06-13.6mum). 2. These dyes (covalently linked to Dextran 40) inhibit bovine heart cyclic nucleotide phosphodiesterase. Reactive Blue 2 (covalently linked to Dextran 40) is a competitive inhibitor of the phosphodiesterase (K(i) 0.4mum). 3. Bovine heart cyclic nucleotide phosphodiesterase is retained on a column of Reactive Blue 2-Sephacryl S-200 and can be eluted from the column by 3':5'-cyclic AMP. 4. A variety of the dyes (either free or covalently linked to Dextran 40) are competitive inhibitors of rabbit muscle lactate dehydrogenase. 5. The effectiveness of a wide range of structurally dissimilar dyes as competitive inhibitors of lactate dehydrogenase and cyclic nucleotide phosphodiesterase compromises proposals for the use of Reactive Blue 2 as a specific probe for the dinucleotide-binding structural domain present in many dehydrogenases and kinases. Detailed information of the various dyes used has been deposited as Supplementary Publication SUP 50089 (7 pages) at the British Library Lending Division, Boston Spa, Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies can be obtained on the terms indicated in Biochem. J. (1978) 169, 5.
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PMID:The specific interaction of cibacron and related dyes with cyclic nucleotide phosphodiesterase and lactate dehydrogenase. 21 44

1. A heat-stable modulator protein was partially purified from mouse epidermis. The protein stimulated modulator-depleted cyclic AMP phosphodiesterase from bovine brain in the presence of Ca2+. 2. DEAE-cellulose chromatography of epidermal extracts demonstrated the presence of two main phosphodiesterase activities that hydrolysed both cyclic AMP and cyclic GMP. A minor peak was eluted between 0.1 and 0.3 M-sodium acetate and a major peak was eluted between 0.3 and 0.45 M-sodium acetate. 3. Cyclic AMP phosphodiesterase activity eluted at low salt concentrations was markedly activated by the epidermal modulator protein in the presence of Ca2+. Storage of the enzyme led to a decrease in its sensitivity to the protein modulator. 4. Treatment of mouse skin with the tumour promoter 12-O-tetradecanoylphorbol 13-acetate, which leads to an increase in epidermal cyclic nucleotide phosphodiesterase activity, did not alter the amount of modulator present in soluble epidermal extracts. The tumour promoter decreased the amount of modulator extractable from particulate epidermal preparations with Triton X-100.
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PMID:Calcium-dependent protein modulator of cyclic nucleotide phosphodiesterases from mouse epidermis. 21 52

The presence and properties of cyclic 3',5'-adenosine monophosphate phosphodiesterase (cAMP-PDIE) and cyclic 3',5'-guanosine monophosphate phosphodiesterase (cGMP-PDIE) were studied in glomeruli isolated from rat renal cortex by sieving and density gradient centrifugation. The specific activity of cGMP-PDIE was higher than the specific activity of cAMP-PDIE in glomeruli; in tubules and renal cortical slices, the specific activity of cAMP-PDIE was higher than that of cGMP-PDIE. In homogenates, X 100,000g supernate of homogenate (cytosol) and X 100,000g pellet (membrane fraction) from glomeruli, the specific activity of cGMP-PDIE was significantly higher than it was in analogous preparations from tubules or renal cortical slices. Cyclic 3',5'-GMP (10(-6)M to 10(-5)M) stimulated glomerular cAMP-PDIE, but it was without effect on cAMP-PDIE from tubules. Structural analogs of cyclic 3',5'-GMP or 5'-GMP did not stimulate glomerular cAMP-PDIE. Cyclic 3',5'-AMP slightly inhibited cGMP-PDIE from both glomeruli and tubules. N6-,2'-0-dibutyryl cyclic 3',5'-AMP inhibited cAMP-PDIE, but not cGMP-PDIE. The addition of calcium increased the activity of cGMP-PDIE, mainly in tubules, but was without effect on cAMP-PDIE. These results suggest the predominance of cyclic 3',5'-GMP catabolism in glomeruli in comparison with other cortical structures, and they demonstrate that both the specific activities and regulatory properties of cyclic nucleotide phosphodiesterase in glomeruli differ markedly from tubules or unfractionated renal cortical tissue.
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PMID:Cyclic nucleotide phosphodiesterases in glomeruli of rat renal cortex. 22 Apr 59

The Ca2+-dependent regulator protein (CDR) of cyclic nucleotide phosphodiesterase (PDE) was reported to be a Ca2+-dependent regulator of microtubule (MT) assembly in the preceding paper. In this paper, the binding of Ca2+-CDR complex to tubulin dimer was investigated in order to elucidate the Ca2+-dependent inhibitory action of CDR on MT assembly. Purified microtubular proteins (PMPs) isolated from porcine brain did not affect the ability of CDR to activate Ca2+-activatable PDE, and did not include any inhibitory protein of Ca2+-activatable PDE. The binding of CDR to the tubulin dimer was observed on Sephadex G-200 gel filtration and ammonium sulfate fractionation in a Ca2+-dependent manner. CDR did not bind to microtubule associated proteins. We now assume that Ca2+-dependent inhibition of MT assembly by CDR is due to the binding of CDR to tubulin dimer in a Ca2+-dependent manner.
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PMID:The interactions between calcium-dependent regulator protein of cyclic nucleotide phosphodiesterase and microtubule proteins. II. Association of calcium-dependent regulator protein with tubulin dimer. 22 51

A membrane fraction prepared from isolated rat adipocytes contained an insulin-sensitive cyclic nucleotide phosphodiesterase (EC 3.1.4.17) which catalyzed the hydrolysis of both adenosine 3',5'-monophosphate (cAMP) and guanosine 3',5'-monophosphate (cGMP). The rate of hydrolysis of cGMP was about one-third that of cAMP. The hydrolysis of the two nucleotides appeared to be assoicated with one catalytic site: one nucleotide interfered with the hydrolysis of the other, in a manner predictable from the kinetic constants in that the Km of one nucleotide as a substrate was comparable to its Ki as an inhibitor of the hydrolysis of the other nucleotide. Incubation of the adipocytes with insulin increased the Vmax of phosphodiesterase without affecting the Km values for either substrate. After adipocytes had been treated with filipin, a membrane perturbant, at a concentration that did not cause cell lysis, the response of phosphodiesterase to insulin was obliterated. Further, the insulin-stimulated phosphodiesterase activity was reversed when hormone-treated cells were subsequently incubated with this agent. These results suggest that the response of membrane phosphodiesterase to insulin is impaired once adipocytes have been exposed to filipin, either preceding or following the incubation with insulin.
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PMID:Filipin prevents and reverses insulin stimulation of rat adipocyte phosphodiesterase. 22 98

The calcium-dependent regulatory protein (CDR).Ca2+ sensitive cyclic nucleotide phosphodiesterase was purified to apparent homogeneity from bovine heart by using ammonium sulfate fractionation, DEAE-ceelulose chromatography, and CDR-Sepharose affinity chromatography. The enzyme was purifed 13 750-fold with a 10% yield and a specific activity of 275 mumol of cAMP min-1 mg-1. The purified enzyme ran as a single band during sodium dodecyl sulfate-polyacrylamide gel electrophoresis with an apparent molecular weight of 57 000. Phosphodiesterase activity was stimulated 10-fold by Ca2+ and CDR with half-maximal activation occurring at 9 ng/assay. [125I]CDR was cross-linked to the purified phosphodiesterase by using dimethyl suberimidate Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the cross-linked products revealed a number of discrete 125I-labeled bands. The molecular weights of the cross-linked products indicate that the stoichiometry of the phosphodiesterase complex is A2C2, where A is the phosphodiesterase catalytic subunit and C is the calcium-dependent regulatory protein.
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PMID:Cross-linking of iodine-125-labeled, calcium-dependent regulatory protein to the Ca2+-sensitive phosphodiesterase purified from bovine heart. 22 4

The regulatory role of cyclic nucleotide phosphodiesterase(s) and cyclic AMP metabolism in relation to progesterone production by gonadotropins has been studied in isolated rat ovarian cells. Low concentrations of choriogonadotropin (0.4-5ng/ml) increased steroid production without any detectable increase in cyclic AMP, when experiments were carried out in the absence of phosphodiesterase inhibitors. The concentration of choriogonadotropin (10ng/ml) that stimulated progesterone synthesis maximally resulted in a minimal increase in cyclic AMP accumulation and choriogonadotropin binding. Choriogonadotropin at a concentration of 10ng/ml and higher, however, significantly stimulated protein kinase activity and reached a maximum between 250 and 1000ng of hormone/ml. Higher concentrations (50-2500ng/ml) of choriogonadotropin caused an increase in endogenous cyclic AMP, and this increase preceded the increase in steroid synthesis. Analysis of dose-response relationships of gonadotropin-stimulated cyclic AMP accumulation, progesterone production and protein kinase activity revealed a correlation between these responses over a wide concentration range when experiments were performed in the presence of 3-isobutyl-1-methylxanthine. The phosphodiesterase inhibitors papaverine, theophylline and 3-isobutyl-1-methylxanthine each stimulated steroid production in a dose-dependent manner. Incubation of ovarian cells with dibutyryl cyclic AMP or 8-bromo cyclic AMP mimicked the steroidogenic action of gonadotropins and this effect was dependent on both incubation time and nucleotide concentration. Maximum stimulation was obtained with 2mm-dibutyryl cyclic AMP and 8-bromo cyclic AMP, and this increase was close to that produced by a maximally stimulating dose of choriogonadotropin. Other 8-substituted derivatives such as 8-hydroxy cyclic AMP and 8-isopropylthio cyclic AMP, which were less susceptible to phosphodiesterase action, also effectively stimulated steroidogenesis. The uptake and metabolism of cyclic [(3)H]AMP in ovarian cells was also studied in relation to steroidogenesis. When ovarian cells were incubated for 2h in the presence of increasing concentrations of cyclic [(3)H]AMP, the radioactivity associated with the cells increased almost linearly up to 250mum-cyclic [(3)H]AMP concentration in the incubation medium. The (3)H label in the cellular extract was recovered mainly in the forms ATP, ADP, AMP, adenosine and inosine, with cyclic AMP accounting for less than 1% of the total tissue radioactivity. Incubation of cyclic AMP in vitro with ovarian cells resulted in a rapid breakdown of the nucleotide in the medium. The degradation products in the medium have been identified as AMP, adenosine and inosine. The rapid degradation of cyclic AMP by phosphodiesterase(s) makes it difficult to correlate changes in cyclic AMP concentrations with steroidogenesis. These observations thus provide an explanation for the previously observed lack of cyclic AMP accumulation under conditions in which low doses of choriogonadotropin stimulated steroidogenesis without any detectable changes in cyclic AMP accumulation.
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PMID:Receptor-mediated gonadotropin action in the ovary. Regulatory role of cyclic nucleotide phosphodiesterase(s) in intracellular adenosine 3':5'-cyclic monophosphate turnover and gonadotropin-stimulated progesterone production by rat ovarian cells. 22 66


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