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

---

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

The regulation of three Salmonella typhimurium phosphatases in reponse to different nutritional limitations has been studied. Two enzymes, an acid hexose phosphatase (EC 3.1.3.2) and a cyclic phosphodiesterase (EC 3.1.4.d), appear to be regulated by the cyclic adenosine 3' ,5'-monophosphate (AMP) catabolite repression system. Levels of these enzymes increased in cells grown on poor carbon sources but not in cells grown on poor nitrogen or phosphorus sources. Mutants lacking adenyl cyclase did not produce elevated levels of these enzymes in response to carbon limitation unless cyclic AMP was supplied. Mutants lacking the cyclic AMP receptor protein did not produce elevated levels of these enzymes in response to carbon limitation regardless of the presence of cyclic AMP. Since no specific induction of either enzyme could be demonstrated, these enzymes appear to be controlled solely by the cyclic AMP system. Nonspecific acid phsphatase activity (EC 3.1.3.2) increased in response to carbon, nitrogen, phosphorus, or sulfur limitation. The extent of the increase depended on growth rate, with slower growth rates favoring greater increases, and on the type of limitation. Limitation for either carbon or phosphorus resulted in maximum increases, whereas severe limitation of Mg2+ caused only a slight increase. The increase in nonspecific acid phosphatase during carbon limitation was apparently not mediated by the catabolite repression system since mutants lacking adenyl cyclase or the cyclic AMP receptor protein still produced elevated levels of this enzyme during carbon starvation. Nor did the increase during phosphorus limitation appear to be mediated by the alkaline phosphatase regulatory system. A strain of Salmonella bearing a chromosomal mutation, which caused constitutive production of alkaline phosphatase (introduced by an episome from Escherichia coli), did not have constitutive levels of nonspecific acid phosphatase.
...
PMID:Regulation of two phosphatases and a cyclic phosphodiesterase of Salmonella typhimurium. 19 13

A preparation of poly(adenosine diphosphoribose) synthase obtained from pigeon liver nuclei has been used to make poly(adenosine diphosphoribose) with an average chain length of 20. Digestion of the purified poly(adenosine diphosphoribose) with snake venom phosphodiesterase (oligonucleate 5'-nucleotidohydrolase; EC 3.1.4.1) gave the monomer, 2'-(5"-phosphoribosyl)-5-AMP. After purification of the monomer on a Dowex-1 column, further digestion with alkaline phosphatase [orthophosphoric-monoester phosphohydrolase (alkaline optimum); EC 3.1.3.1] yielded the dephosphorylated product, 2'-ribosyl adenosine. Nuclear magnetic resonance spectra at 360 MHz of the 2'-ribosyl adenosine were obtained in [2H6]dimethylsulfoxide, which allows direct observation of the hydroxyl protons. These spectra show the absence of the adenosine 2'-hydroxyl proton, thus confirming the 2' position as the site of attachment of the ribose to the adenosine moiety. Comparison of the coupling constants and the chemical shifts of the ribose hydroxyl protons of 2'-ribosyl adenosine with the model compounds alpha- and beta-methylribofuranoside establishes an alpha (1" leads to 2') glycosidic linkage in the monomer. No evidence was found for heterogeneity in either the site of attachment or configuration of the linkage in the 2'-(5"-phosphoribosyl)-5'-AMP.
...
PMID:Structure of a poly (adenosine diphosphoribose) monomer: 2'-(5"-hosphoribosyl)-5'-adenosine monophosphate. 20 34

Haemoglobin-free human erythrocyte ghosts that were prepared in the presence of EDTA and were then exposed to Ca2+ showed a substantial loss of phosphatidylinositol phosphate and phosphatidylinositol diphosphate, measured either chemically or by loss of 32P from the lipids of prelabelled membranes. At the same time there was, as reported previously (Allan, D. and Michell, R.H., (1976) Biochim. Biophys. Acta 455, 824--830), and approximately equivalent rise in the diacylglycerol content of the membranes. Analysis of the 32P-labelled water-soluble material released during this process showed that the major products were inositol diphosphate and inositol triphosphate. No change was seen in the phosphatidylinositol or phosphatidate content of the membranes, and there was no Ca2+-activated loss of 32P from the phosphatidate of prelabelled membranes: this suggests that Ca2+ did not activate phosphoinositide phosphomonoesterases or phosphatidate phosphomonoesterase in human erythrocyte membranes. It is concluded that human erythrocyte membranes contain at their cytoplasmic surface a Ca2+-activated phosphodiesterase that is active against both phosphatidylinositol phosphate and phosphatidylinositol diphosphate. Rabbit erythrocytes also contained this enzyme, but in these cells there was also evidence for the presence of a Ca2+-activated phosphatidate phosphomonoesterase.
...
PMID:A calcium-activated polyphosphoinositide phosphodiesterase in the plasma membrane of human and rabbit erythrocytes. 20 46

The rabbit iris smooth muscle has been shown to contain triphosphoinositide phosphomonoesterase (phosphatidyl-myo-inositol-4,5-bisphosphate phosphohydrolase, EC 3.1.3.36) and phosphodiesterase (triphosphoinositide inositoltrisphosphohydrolase, EC 3.1.4.11) activities. Under our experimental conditions about 77% of the phosphomonoesterase and 61% of the phosphodiesterase activities were localized in the particulate fraction. The kinetic properties of the enzymes in the microsomal fraction were examined. The enzyme preparation was specific to polyphosphoinositides; it did not attack phosphatidylinositol under the present assay condition. The effects of Ca2+ and Mg2+ were also studied. Although the microsomal enzymes did not require added divalent cations for their activities, both the phosphomonoesterase and phosphodiesterase were appreciably inhibited by 1 mM EDTA. Phosphodiesterase and phosphomonoesterase were stimulated by Ca2+ and Mg2+, respectively. The demonstration of triphosphoinositide phosphodiesterase in the iris muscle, coupled with the findings that this enzyme is activated by Ca2+ and is not influenced by acetylcholine add further support to our previous conclusion (J. Pharmacol. Exp. Ther. (1978) 204, 655--668; J. Neurochem. (1978) 30, 517--525) that an increased Ca2+ influx, following the interaction between the neurotransmitter and its receptor, could act to stimulate the phosphodiesterase, thus leading to increased triphosphoinositide breakdown and increased phosphatidic acid via increased diacylglycerol.
...
PMID:Studies on the properties of triphosphoinositide phosphomonoesterase and phosphodiesterase of rabbit iris smooth muscle. 21 33

Purified phosphodiesterase-phosphomonoesterase was found to be composed of four isozymes with different isoelectric points. These isozymes, phosphodiesterase-phosphomonoesterases 1-4, were separated from one another by repeated isoelectric focusing. Very little difference in amino acid composition, enzymic properties or circular dichroism spectra was detected among the isozymes. Far-ultraviolet circular dichroism spectra showed that the enzyme contained about 10% alpha-helix and 40% beta-structure. Phosphodiesterase-phosphomonesterase is a glycoprotein, because it was adsorbed on concanavalin A-Sepharose 4B and gave a band of carbohydrate coincident with that of protein or enzymic activity on polyacrylamide disc gel electrophoresis. Carbohydrate analyses revealed that the enzyme contained 37 micron of N-acetylglucosamine and 358 micron of mannose per mg of protein. The carbohydrate contents of the four isozymes were almost the same.
...
PMID:Phosphodiesterase-phosphomonesterases from Fusarium moniliforme. Separation and properties of four isozymes. 21 23

In the presence of phosphomonoesterase contaminations the use of bis-p-nitrophenyl phosphate to measure phosphodiesterase activity gives inconclusive values because one of the products of the phosphodiesterase or nuclease reaction becomes a substrate of the contaminating enzyme. A direct determination of the hydrolyzed phosphodiesterase substrate in the UV range is possible at the isosbestic points of the transformation of the phosphomonoesterase substrate.
...
PMID:Determination of phosphodiesterase activity in the presence of phosphomonoesterase using bis-p-nitrophenyl phosphate. 22 67

A ribonuclease (ribonucleate 3-pyrimidine-oligonucleotidohydrolase, EC 3.1.4.22) was purified 8300-fold from soluble fraction of beef brain and its properties were investigated. The enzyme is an endonuclease capable of hydrolyzing tRNA, rRNA, poly(C), but shows no activity towards poly(U), poly(A), and poly(G). The preparation is free of deoxyribonuclease, non-specific phosphodiesterase and phosphomonoesterase activity. The enzyme has a pH optimum of 7.6, is not heat stable, has a molecular weight of 25 000, and has a K-m of 134 mu rRNA and K-m of 1600 mug poly(C) per ml.
...
PMID:Purification of an alkaline ribonuclease from soluble fraction of beef brain. 23 61

A cyclic nucleotide-binding phosphohydrolase that possesses both a phosphomonoesterase and a phosphodiesterase catalytic function has been partially purified from Aspergillus nidulans. The enzyme hydrolyzes both p-nitrophenylphosphate and bis-(p-nitrophenyl)-phosphate. o'-Nucleoside monophosphates are the best physiological phosphomonesterase substrates but 5'- and 2'-nucleoside monophosphates are also hydrolyzed. The enzyme catalyzes the hydrolysis of adenosine 5'-triphosphate, adenosine 5'-diphosphate, and 2',3'- and 3'5'-cyclic nucleotides, but not of ribonucleic acid, deoxyribonucleic acid, or nicotinamide adenine dinucleotide. The enzyme has acid pH optima and is not activated by divalent cations. Nucleosides and nucleotides inhibit the enzyme. Cyclic nucleotides are competitive inhibitors of the phosphodiesterase-phosphomonoesterase. The enzyme can occur extracellularly. The phosphodiesterase-phosphomonoesterase is present at high levels in nitrogen-starved mycelium, and it is strongly repressed during growth in media containing ammonium or glutamine and weakly repressed during growth in glutamate-containing medium. Experiments with various area mutants show that this regulatory gene is involved in the control of the enzyme. No evidence for regulation of the enzyme by carbon or phosphorus starvation has been found.
...
PMID:Enzymology and genetic regulation of a cyclic nucleotide-binding phosphodiesterase-phosphomonoesterase from Aspergillus nidulans. 24 43

1. An endonuclease has been isolated from the nuclei of rye (Secale cereale L) germ and partially purified. The enzyme shows optimum activity over the pH range 5.4-7.4 towards both DNA and RNA, and has no phosphomonoesterase or phosphodiesterase activity. 2. DNA is degraded by the rye germ nuclease to oligonucleotides of similar size, and RNA to oligonucleotides and mononucleotides containing a C-terminal 5'-phosphate group. 3. The rate of hydrolysis of nuclear acids by the enzyme decreases in the following order: native DNA greater than denatured DNA greater than RNA. Synthetic polynucleotides are hydrolysed at a rate decreasing in the order: poly(A) greater than poly(U) greater than poly(C) greater than poly(G).
...
PMID:Purification and some properties of a nuclease from rye germ nuclei. 61 Feb 81

We report a technique for the isolation of plasma membranes from gel-filtered platelets exposed to thrombin, using 125I-labeled lentil lectin as an external marker. Labeled cells not exposed to thrombin could be lysed on a gradient of glycerol. Those cells incubated with thrombin (without external Ca2+) were made more susceptible to breakage on a gradient of glycerol-EDTA, and homogenized with a zero-clearance homogenizer. Lysates were spun on gradients of sodium diatrizoate. The membranes obtained from such gradients have been examined by electron microscopy and by assays for enzymes and 125I label. Membranes from platelets incubated without and with thrombin were found to be enriched as follows: lectin marker, 8- and 9-fold, respectively; phosphodiesterase, 9- and 12-fold; acid phosphatase, 2.5 and 2-fold. There is thus a particularly close correlation of lectin marker with phosphodiesterase, an enzyme characteristic of normal purified membranes. Monitoring for 125I-labeled lentil lectin appears to be a useful procedure for following platelet membranes during isolations from relatively small quantities of blood.
...
PMID:Isolation of membranes from normal and thrombin-treated gel-filtered platelets using a lectin marker. 81 77


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---