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)

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

Radioimmunoassay of cyclic AMP (cAMP) in the islets of Langerhans from 48-64 h old Rats was performed after succinylation of the samples. cAMP was detected at 0.03 nM. The cAMP content of islets increases when L-arginine, L-lysine and L alanine are added together in the incubation medium at a concentration of 5-10 mM each. When phosphodiesterase is inhibited by theophylline the three amino acids considerably increase the cAMP content of islets. Thus an increase in cAMP content of the islets was observed with a concentration of amino acids which is efficient in stimulating the insulin and glucagon secretion.
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PMID:[Measurement of cyclic AMP in the islets of Langerhans of newborn rats. Effect of amino acids]. 19 68

A Ca2+-dependent regulator protein of cyclic 3':5'-nucleotide phosphodiesterase (EC 3.1.4.17) has previously been isolated from rat testis and shown to be a heat-stable, Ca2+-binding protein with a molecular weight of approximately 17,000. The Ca2+-dependent regulator protein is also structurally similar to troponin-C, the Ca2+-binding component of muscle troponin and Ca2+ mediator of muscle contraction. The present report describes a partial amino acid sequence of the Ca2+-dependent regulator. The protein (148 amino acids) is 50% homologous with skeletal muscle troponin-C, but is 11 residues shorter than the muscle protein. The Ca2+-dependent regulator protein has an NH2-terminal sequence of acetyl-Ala-Asp-Glu, a COOH-terminal sequence of Thr-Ala-Lys and 1 residue of epsilon-trimethyllysine located at position 115. All of these properties are distinct from those of other homologous Ca2+-binding proteins. These properties may account for the biological specificities demonstrated by these proteins as compared to the Ca2+-dependent regulator protein. Based on the sequence and a comparison of the Ca2+-dependent regulator protein to other calcium-binding proteins, our data support the view that all of these moecules contain common sequences, especially at their proposed metal-binding sites.
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PMID:Sequence homology of the Ca2+-dependent regulator of cyclic nucleotide phosphodiesterase from rat testis with other Ca2+-binding proteins. 20 28

Mouse L Cells, grown in suspension culture can be rendered permeable to exogenous deoxynucleoside triphosphates by a cold shock in a near isotonic buffer system. These cells use the deoxynucleotides to synthesize DNA in a semiconservative fashion. The addition of 0.05% Triton X-100 to this system increases the permeability of the cells so that exogenously supplied macromolecules gain access to the DNA. When DNAase and phosphodiesterase are added to the detergent-permeabilized cells, the cell DNA is rapidly degraded, demonstrating that the enzymes reach the DNA within the first 2 min of the incubation period. Addition of whole calf thymus histone or histone fractions to the detergent-permeabilized cells inhibits DNA synthesis. The lysine-rich histone, F is a more effective inhibitor than the arginine-rich histone, F3. The other histone fractions including the slightly lysine-rich fractions, F2a and F2b, are intermediate between F1 and F3 as inhibitors of DNA- synthesis. Kinetic analysis demonstrates that the added histones increase apparent Km and reduce V of DNA synthesis in the permeabilized cells. These studies suggest the possibility that histones alter the association of the DNA replication complex and the DNA template in a manner that reduces the rate of DNA synthesis.
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PMID:Histone inhibition of DNA synthesis in eukaryotic cells permeable to macromolecules. 96 82

We previously characterized human placental cytosolic cAMP phosphodiesterase (PDE) and found that two low K(m) cAMP PDE isoforms that were very sensitive to inhibition by cGMP and cilostamide were activated by insulin. As a first step toward understanding the mechanisms by which insulin activates this enzyme, we purified the cGMP-inhibited low K(m) cAMP PDE (cGI-PDE) from human placentas. The enzyme was purified 11,700-fold from a pool of 100,000 x g supernatant fractions of 10-15 placentas by ammonium sulfate precipitation, diethylaminoethyl-cellulose chromatography, and affinity chromatography, using an isothiocyanate derivative of cilostamide (CIT-agarose). The specific activity of the affinity-purified enzyme was 432 +/- 17 nmol/min.mg (mean +/- SD; n = 4). Gel permeation chromatography of the CIT-agarose eluates revealed one protein peak that coincided with PDE activity at an elution position of 135,000 daltons. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of this protein peak and CIT-agarose eluates revealed the same patterns, indicating that the purified PDE preparations contained multiple proteins with apparent mol wt of 138K, 83K, 72K, 67K, 63K, and 44K. The 138K form appears to be an intact enzyme; an analogous approximately 135K form has recently been identified in rat adipocyte particulate fractions by specific immunoprecipitation or Western immunoblots. In addition, other smaller forms eluted at 135,000 daltons on gel permeation chromatography, suggesting that, although proteolyzed, they must have been associated by either noncovalent interactions or disulfide bonds. All of the protein bands observed on the sodium dodecyl sulfate-polyacrylamide electrophoresis gel reacted with rabbit antibodies raised against human platelet cGI-PDE. Ten peptides from endoproteinase Lys-C-digests of the affinity-purified placental cGI-PDE were isolated and sequenced; sequences of eight peptides were identical to the deduced amino acid sequences in the C-terminal half of a human heart cGI-PDE cDNA, while those of two peptides were not found in the heart enzyme. The sequences of the eight peptides also matched peptide sequences derived from a purified human platelet cGI-PDE. These results provide evidence that the catalytic C-terminal half domain of the placental insulin-sensitive cGI-PDE shares homology with those of human heart and platelet cGI-PDEs. K(m) and maximum velocity values for cAMP and cGMP were 0.57 microM and 862 nmol/min.mg, and 15 microM and 467 nmol/min.mg, respectively. ED50 values for cGMP, cilostamide, and Ro 20-1724 were 0.12, 0.22, and 120 microM, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Purification and characterization of guanosine 3',5'-monophosphate-inhibited low K(m) adenosine 3',5'-monophosphate phosphodiesterase from human placental cytosolic fractions. 131 79

A 32P-labeled protein that co-purified with acidic fibroblast growth factor (aFGF) receptor from bovine liver proved to be a distinct membrane protein, which itself has kinase activity that is stimulated by aFGF. The protein was designated MAFP for major aFGF-stimulated phosphoprotein. MAFP was purified from bovine liver using immunoaffinity chromatography with monoclonal antibody to MAFP following Triton X-100 extraction of plasma membranes and wheat germ lectin-Sepharose 4B column chromatography. The purified MAFP showed molecular masses of 130 kDa and 260 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing and nonreducing conditions, respectively. Purified MAFP elicited aFGF-stimulated Thr-specific autophosphorylation activity and phosphorylation activity toward protein substrates (myelin basic protein and histone). Amino acid sequence analyses of 16 peptide fragments of MAFP, produced by endoproteinase Lys-C digestion followed by reduction and S-pyridylethylation, showed approximately 80-100% homology with the cDNA-deduced amino acid sequences of human and mouse plasma cell membrane glycoprotein, PC-1 (Buckley, M. F., Loveland, K. A., McKinstry, W. J., Garson, O. M., and Goding, J. W. (1990) J. Biol. Chem. 265, 17506-17511), suggesting that MAFP is the bovine version of PC-1. The amino acid sequences of bovine MAFP, human and mouse PC-1 reveal a putative ATP binding site in their extracellular domains. These results suggest that MAFP(PC-1) is an ectoprotein kinase. In addition to the kinase activity, MAFP(PC-1) was also found to possess alkaline nucleotide phosphodiesterase activity. It is now clear that several of the unique properties previously attributed to the aFGF receptor kinase are actually properties of this novel Thr-specific ectoprotein kinase, which co-purifies with the aFGF receptor and is responsive to stimulation by aFGF.
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PMID:The plasma cell membrane glycoprotein, PC-1, is a threonine-specific protein kinase stimulated by acidic fibroblast growth factor. 171 69

Effect of protein deficient diet on hepatic plasma membrane fluidity has been studied in rats using (i) steady state fluorescence polarization and anisotropy, (ii) phospholipid and cholesterol contents, (iii) phospholipid fatty acid composition, (iv) turnover of phosphatidyl choline (PC), and (v) activities of membrane-bound enzymes as parameters and rats fed casein (20%) diet as standard group. A significant increase in steady state fluorescence and anisotropy values was registered in the deficient group, indicating increased resistance and hence decrease in fluidity of the plasma membrane. Supplementation of the diet with lysine and threonine improved these values, thereby suggesting the significance of diet for membrane fluidity. Simultaneous significant alterations in other parameters, viz. (i) decrease in PC, PE and free cholesterol and increase in esterified cholesterol contents, (ii) decrease in unsaturation of fatty acids of PC, (iii) decrease in incorporation of NaH2 32PO4, [CH3-14C]choline and [CH3-14C]methionine into plasma membrane PC, and (iv) decrease in activities of plasma membrane 5'-nucleotidase and phosphodiesterase along with increase of (Na(+)-K+)ATPase and adenyl cyclase, were observed in the deficient group which on supplementation with lysine and threonine showed improvement over alterations.
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PMID:Hepatic plasma membrane fluidity and dietary proteins. 175 32

In order to study the role of individual amino acids in the function of the inhibitory subunit, gamma, of retinal rod phosphodiesterase (PDE), the following substitutions were made: Arg-24----Gly, Lys-29----Thr, Arg-33----Gly, Lys-39----Thr, Lys-41----Thr, Lys-44----Thr, Lys-45----Thr, Glu-77----Gly, and Tyr-84----Ala. Deletion of seven C-terminal amino acids (delta 81-87) was also investigated, and the activity of all the mutant PDE gamma forms determined. Expression of the mutant PDE gamma genes was achieved by sequential in vitro transcription and translation. The results suggest that PDE gamma fragment 24-33, which is rich in basic amino acids, and in particular Arg-24, is essential for PDE gamma binding both to the catalytic subunits (alpha and beta) of phosphodiesterase (PDE alpha beta) and to the alpha-subunit of transducin (T alpha), the GTP-binding protein found in retinal rods that activates cyclic GMP PDE. In contrast, the C-terminal fragment of PDE gamma participates in phosphodiesterase inhibition and in binding to T alpha, but not in binding to PDE alpha beta.
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PMID:Site-directed mutagenesis of the inhibitory subunit of retinal rod cyclic GMP phosphodiesterase. 196 21

The acyl carrier protein (ACP) phosphodiesterase of Escherichia coli catalyzes the hydrolytic cleavage of the 4'-phosphopantetheine residue from ACP, with the generation of apo-ACP (P. R. Vagelos and A. R. Larrabee, J. Biol. Chem. 242:1776-1781, 1967). Although it has been postulated to play a role in the regulation of fatty acid synthesis, presently available evidence makes this unlikely, and its physiological function requires further investigation. We have now purified the enzyme from E. coli more than 3,000-fold and have identified it as a protein of Mr 25,000, as judged from its migration during electrophoresis in gels containing sodium dodecyl sulfate. The enzyme has remarkable thermostability, being protected against irreversible inactivation at 90 degrees C by the presence of sodium dodecyl sulfate. A partial sequence of the amino terminus of the enzyme is as follows: H2N-Ser-Lys-Val-Leu-Val-Leu-Lys-Ser-?-Ile-Leu-Ala-Gly-Tyr-Ser-. Other properties of the enzyme are also described.
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PMID:Isolation and properties of acyl carrier protein phosphodiesterase of Escherichia coli. 216 83

The venom from Crotalus molossus nigrescens contains many activities including: hyde powder azure proteinase; N-benzoyl-arginine-ethyl-ester hydrolase; phospholipase; phosphodiesterase; desoxyribonuclease; fibrinogen coagulase; collagenase, fibrinolytic activity, and hemorrhagic factors. The venom, assayed with amounts of venom up to 50 micrograms protein per assay, does not contain acetylcholinesterase, phosphatase, amylase, ribonuclease, tyrosyl-ester hydrolase or hyaluronidase activities. The venom is lethal to mice with an i.p. LD50 of 2.35 mg/kg mouse. Fractionation of soluble venom by Sephadex G-75 separates at least five families of components. Fractions I-III contains all the enzymes, and fraction V have six small peptides. Further separation of fractions II-III on diethyl-amino-ethyl-cellulose columns at pH 8.0 and 8.3 gave pure proteinase E with a mol. wt of 21,390 and the following N-terminal amino acid sequence; Phe-Ala-Lys-Arg-Tyr-Val-Glx-Leu-Val-Ile-Val-Ala. A thrombin-like enzyme with a mol. wt of 75,000 was also purified from this venom by means of affinity and ion exchange chromatographies.
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PMID:Characterization of the venom from Crotalus molossus nigrescens Gloyd (black tail rattlesnake): isolation of two proteases. 218 98


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