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)

The activities of guanylate cyclase, guanosine 3', 5'-monophosphate (cyclic GMP) phosphodiesterase and 5'-nucleotidase were measured during postnatal development in retinas of control and C3H/HeJ mice. In control retina, each of these enzyme activities increases in conjunction with photoreceptor cell differentiation and maturation. In C3H retina, guanylate cyclase and 5-nucleotidase activities increase with photoreceptor cell development and decrease with photoreceptor cell death. However, the activity of a class of cyclic GMP phosphodiesterase which distinguishes the photoreceptor cells of control mice and those of several other species is not demonstrable in retina of C3H mice at any age. It is suggested that the deficiency in cyclic GMP phosphodiesterase activity may account for the accumulation of cyclic GMP which has been shown to occur in the C3H photoreceptor cells before they degenerate.
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PMID:Enzymic basis for cyclic GMP accumulation in degenerative photoreceptor cells of mouse retina. 0 93

A simple method, involving NAD+-Sepharose chromatography, was developed for the preparation of snake venom phosphodiesterase (EC 3.1.4.1) almost free from 5'-Nucleotidase (EC 3.1.3.5). Using an NAD+-Sepharose 4B column, phosphodiesterase was eluted in the unadsorbed fraction, whereas 5'nucleotidase was strongly adsorbed. The latter enzyme was desorbed when 0.2 M sodium bicarbonate buffer containing 1mM beta-NADH was used as a solvent. The affinity column could be used at least four times without any decrease of potency, and the method was applicable for the preparation of phosphodiesterase from the venoms of rattlesnake (Crotalus adamanteus) and Japanese mamushi (Agkistrodan halys blomhoffi).
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PMID:A simple method for preparation of snake venom phosphodiesterase almost free from 5'-nucleotidase. 16 89

Previous studies have indicated that rat luteal cells at certain stages of development can be fractionated so as to obtain two plasma membrane fractions with different densities and different profiles of marker enzymes. The light membrane fractions (density 1.13) contain the majority of hCG-binding sites and little or no cyclase enzyme, while the heavy membranes (density 1.17) contain the majority of cyclase enzyme and lesser quantities of hormone-binding sites. These membrane fractions were further compared with respect to their susceptibility to perturbation by digitonin. The buoyant density of luteal cell light membrane fractions, as marked by [125I]iodo-hCG binding, Mg2+-dependent ATPase, and 5'-nucleotidase, were highly perturbable by digotonin (delta density, greater than 0.05), while adenylate cyclase activity and phosphodiesterase activity associated with this fraction were only slightly perturbed (delta density, less than 0.02). The buoyant density of luteal cell heavy membrane fractions, as marked by adenylate cyclase, ATPase, and nucleotidase, was not significantly perturbed by digotonin. The hCG binding associated with the heavy membrane fraction was not perturbed by digitonin. From these studies, we conclude that the adenylate cyclase activity associated with light membrane fractions is due to contamination by heavy membranes, while the hCG-binding activity in heavy membrane fractions is intrinsic to that membrane. Except for the lysosomal marker (glucuronidase), which was solubilized by digitonin, the detergent had no significant effect on the density of mitochondrial, Golgi, GERL (Golgi, endoplasmic reticulum, and lysomal), or endoplasmic reticulum membranes. Plasma membranes from isolated granulosa cells and ovaries obtained 24 h after priming with PMS gonadotropin-hCG behaved as heavy membranes (density, 1.17) which contained hCG-binding sites, adenylate cyclase, nucleotidase, and Mg2+-dependent ATPase. These were not significantly perturbed by digitonin. The appearance of light membranes and the segregation of adenylate cyclase from the majority of hCG-binding sites is a development feature of the luteal cell.
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PMID:Interactions of gonadotropins with corpus luteum surface membranes. V. Differential effects of digitonin on the buoyant densities of light and heavy rat ovarian membrane fractions. 43 71

A variety of small peptides bind calmodulin (CaM) and inhibit CaM-dependent enzyme activity. The cyclic peptides cyclosporin A (CSA) and gramicidin-S (GRS) are shown to bind CaM and inhibit 3',5'-cyclic nucleotide phosphodiesterase (PDE) in a calcium-dependent manner. The cyclic peptide microcystin-LR (MLR) and the depsipeptides, valinomycin (VLM) and enniatin-B (ENB), bind to CaM and inhibit PDE activity. Spectral changes exhibited by the binding of MLR, VLM and ENB to dansyl-CaM as compared to that of CSA and GRS reflected different binding sites and/or different conformational changes. The apparent binding constants (Kd) for CaM-peptide were estimated and found to be 4.8 microM for CSA, 2.85 microM GRS, 12.99 microM MLR, 4.29 microM VLM and 41.26 microM ENB. Although these peptides did not inhibit baseline PDE activity, they did inhibit CaM-dependent PDE activity in a dose-dependent manner. Half-maximal inhibition (IC50) of PDE occurred approximately at 0.11 microM MLR; 0.45 microM GRS; and greater than 5 microM for ENB, CSA and VLM. This may be the first observation that these peptides (MLR, VLM and ENB) bind to a known cytoplasmic protein and inhibit an enzyme system dependent on that protein for optimal activity. Interaction of these peptides with CaM may be responsible for creating conformational-functional changes in CaM, thus altering the signal transduction mechanism required for CaM-dependent enzymes, such as cyclic nucleotidase, protein kinases and phospholipase A2.
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PMID:Interaction of cyclic peptides and depsipeptides with calmodulin. 172 18

Isolation and general properties of 3'-5' exonucleases I and II (EC 3.1.4.26), which are specific to single-stranded DNA, are described. Such enzymes, being components of replication complexes, could correct replication errors. Homogeneous exonucleases I and II consist of a single subunit with molecular mass of 50 and 40 kDa, respectively. These enzymes are located preferentially in the nuclear membrane and chromatin. They form complexes with nuclear DNA polymerases and some other proteins and are not observed practically in a free state. Molecular masses of the complexes amount from 70 to 1.500 kDa. The complexes dissociate as a result of solution hydrophobization and can be reconstituted after the decrease of hydrophobization. The heavy membrane complex form of 3'----5' exonuclease I manifests enzymatic activities of DNA polymerase alpha (EC 2.7.7.7), non-specific nucleoside triphosphatase (EC 3.1.3.2), nucleotidase (EC 3.1.3.31) and faint activity of endonuclease (EC 3.1.4.5). Complexes under study do not display activity of thymidine kinase (EC 2.7.1.21), marker protein of replitase, neither in G0 nor in S-period.
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PMID:[Homogeneous 3'----5'-exonucleases and their multienzyme complexes from the rat liver]. 234 19

Identification of cytidine 3',5'-cyclic monophosphate (cyclic CMP) as one of the products resulting from the incubation of dialysed cell-free preparations from rat brain, liver and kidney with cytidine 5'-triphosphate (CTP) is described. The non-acidic precipitable products after incubation of the tissue preparations with unlabelled, with 14C-single labelled, and with 14C- and 32P-dual labelled CTP were examined by thin-layer chromatography and high-pressure liquid chromatography, isotopic ratio determination, UV absorbance spectrophotometry, selective hydrolysis with nucleotidase, phosphodiesterase and acid, and by fast atom bombardment mass spectrometry with mass-analysed ion kinetic energy spectrum scanning. In addition to cyclic CMP and unchanged CTP, the products of the reaction were found to include cytidine monophosphate (CMP) and cytidine diphosphate (CDP) together with four novel cytidine compounds identified as cytidine 3',5'-cyclic pyrophosphate, cytidine 2'-monophosphate 3',5'-cyclic monophosphate, cytidine 2'-O-aspartyl-3',5'-cyclic monophosphate and cytidine 2'-O-glutamyl-3',5'-cyclic monophosphate. The evidence presented constitutes conclusive proof of the natural occurrence of cytidylate cyclase activity; the four novel cytidine cyclic phosphates described provide a feasible explanation of the discrepancies in previous reports which have led to the controversy which exists concerning the existence of cytidylate cyclase activity.
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PMID:Cytidylate cyclase activity: identification of cytidine 3',5'-cyclic monophosphate and four novel cytidine cyclic phosphates as biosynthetic products from cytidine triphosphate. 257 47

The effect of thyroid status on the cyclic nucleotide phosphodiesterase in adipocyte plasma membranes has been studied. In euthyroid rat fat cells, about 7% of the total cAMP phosphodiesterase was found in the plasma membrane. Thyroidectomy doubled both the enzyme's total activity in this fraction, and its specific activity (60 versus 37 pmol/min/mg) compared to euthyroid rat plasma membrane. In membranes from thyroidectomized rats, phosphodiesterase hydrolyzed cAMP with a single Km of 2 microM, whereas in euthyroid rat membranes, Lineweaver Burk plots were non-linear, with apparent Kms of 0.5 and 5 microM. This phosphodiesterase activity was insensitive to exogenous guanine nucleotides and calcium. In vivo injection of triiodothyronine restored phosphodiesterase activity in plasma membranes from thyroidectomized rats to the values obtained for euthyroid rats. Centrifugation on a 10 to 45% sucrose density gradient of the plasma membrane fractions gave two main peaks of phosphodiesterase activity which hydrolyzed the cAMP in adipocyte plasma membranes from both euthyroid and thyroidectomized rats. The distribution profiles for these activities were very similar in the two plasma membrane preparations. The peaks of phosphodiesterase and 5'nucleotidase activity coincided. Thyroidectomy raised the phosphodiesterase activity of these two peaks, particularly of the first. The cAMP phosphodiesterase activities in both hypothyroid and control plasma membrane preparations were also sensitive to insulin and were activated by phospholipase A2 and three anionic phospholipids. Thyroid hormones therefore regulate the degradation of cAMP in plasma membranes by a mechanism which seems different from the one involved in the action of insulin, and is independent of the membrane phospholipid composition.
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PMID:Effects of thyroidectomy, insulin, and phospholipids on cyclic AMP phosphodiesterase in rat adipocyte plasma membranes. 298 21

Several steps of purification (octyl-Sepharose chromatography, Blue Sepharose 6B chromatography and sucrose density gradient centrifugation) led to a highly purified aggregate of the enzymes, 3',5'-cyclic-nucleotide phosphodiesterase (PDE) and nucleotidase. The purified enzyme aggregate showed an S value of 7.3 (SE +/- 0.3, n = 10). Further analysis by SDS-polyacrylamide gel electrophoresis (PAGE) revealed two proteins near 67 and 60 kDa. Dissociation of the 7.3 S enzyme aggregate showed a 3.6 S PDE form and a nucleotidase form at 4.2 S. Additionally, higher S value forms of the nucleotidase up to 17 S have been observed. Apparently, they had formed by self-association. SDS-PAGE of the 17 S nucleotidase form showed only one band at 67 kDa. This was taken as evidence for the homogeneity of the 17 S nucleotidase form and the self-association of the nucleotidase after dissociation from the 7.3 S enzyme aggregate. Furthermore, from this it could be concluded that the 67 kDa protein of the 7.3 S enzyme aggregate should be identified with the nucleotidase, and thus the 60 kDa band represents the PDE.
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PMID:Purification of an enzyme aggregate containing 3',5'-cyclic-nucleotide phosphodiesterase and nucleotidase. 301 49

An alkaline 5'-nucleotidase with properties similar to those of membrane-bound 5'-nucleotidase was recovered in soluble form in the postmicrosomal supernatant fraction (cytosol) of rat liver. The enzyme seems to constitute a quantitatively distinct fraction, since the activity in postmicrosomal supernatants was increased by a further 10% by additional homogenization of livers. Lysosomal acid phosphatase activity increased similarly, whereas other membrane-bound marker enzymes alkaline phosphatase, phosphodiesterase I and glucose-6-phosphatase showed no increase when homogenization of liver tissue was continued. Gel-permeation chromatography and pH-dependence studies indicated that enzyme activity in the supernatant fraction with 0.3 mM-UMP or -AMP as substrate at pH 8.1 was about 85 or 100% specific respectively. In regenerating liver the enzyme recovered in soluble form showed decreased specific activity, in contrast with alkaline phosphatase measured for comparison. The nucleotidase activity per mg of cytosolic protein was 2.1 nmol/min with AMP as substrate. The total activity measured in the postmicrosomal supernatant was 1.5% of the homogenate activity measured in the presence of detergent.
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PMID:The presence and activity in normal and regenerating rat liver postmicrosomal supernatant fraction of an enzyme with properties similar to those of membrane-bound 5'-nucleotidase. 302 68

Nucleotide pyrophosphatase and phosphodiesterase I activities were determined in sera from 126 patients with different types of liver disease and in two additional groups of patients with intra- and extrahepatic cholestasis, respectively. Both activities probably represent the same enzyme, and were positively correlated with alkaline phosphatase, lipoprotein X, and several other tests reflecting cholestasis. Also, we found by discriminant analysis that tests for cholestasis frequently replaced the results of both enzymes. In some groups of liver disease, nucleotide pyrophosphatase and phosphodiesterase I were correlated with the concentrations of prealbumin and albumin. The sensitivity of phosphodiesterase I (and nucleotide phosphatase) is rather low when compared with alkaline phosphatase, and we do not recommend it for use in the clinical routine. Nevertheless, it appears to be of potential value for studies on classification of liver diseases, adding information to a panel of 20 commonly used "liver tests" by appearing in some of the best four test-sets for distinguishing between groups of liver disease by discriminant analysis.
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PMID:Usefulness of serum nucleotide pyrophosphatase and phosphodiesterase I activities in classifying liver disease. 611 26


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