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)

Tyr99 phosphorylation of calmodulin appears to induce a distinct conformational change as is evident from the profound attenuation of the Ca(2+)-induced enhancement of calmodulin's mobility seen during SDS/PAGE. The effect of this conformational change appears to be localized, in that both calmodulin and P-Tyr99-calmodulin show identical dose-dependent activation profiles for stimulation of a physiological effector, type-I (Ca2+/calmodulin-stimulated) cyclic nucleotide phosphodiesterase (PDE) activity and their presence engenders similar dose-dependent PDE activation by Ca2+. In marked contrast with this, with P-Tyr99-calmodulin there were 3-4-fold increases in the IC50 values for inhibition of type-I PDE activity by the calmodulin antagonists TFP and W7, together with increased values for Hill coefficients for inhibition. The polybasic compound poly(L-lysine) potently augmented the action of calmodulin as a PDE activator, causing an approx. 7-fold decrease in the EC50 value for activation of PDE. It is suggested (i) that the Tyr99 phosphorylation of calmodulin, which occurs within a high-affinity Ca(2+)-binding domain, induces a localized conformational change in this peptide which can selectively attenuate the action of calmodulin antagonists on type-I PDE activity while leaving unaffected Ca(2+)-dependent activation, and (ii) that polybasic substances on complexing with calmodulin may serve to enhance the sensitivity of type-I PDE to activation by this regulatory peptide.
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PMID:Phosphorylation of calmodulin on Tyr99 selectively attenuates the action of calmodulin antagonists on type-I cyclic nucleotide phosphodiesterase activity. 819 77

Activation of cGMP phosphodiesterase (PDE) by the rod G-protein transducin is a key event in visual signal transduction in vertebrate photoreceptor cells. Interaction between the GTP-bound form of the alpha-subunit of transducin (alpha t*) and the PDE inhibitory gamma-subunit (P gamma) is a major component of PDE activation. The central polycationic region of P gamma, P gamma-24-45, has been implicated as one of the sites involved in alpha t*.P gamma interaction. Here we determine the site on alpha t* that interacts with P gamma-24-45 using a photo-cross-linking approach. The synthetic peptides Cys(ACM)Tyr-P gamma-24-45-Cys (where ACM indicates acetamidomethyl group) and Cys-P gamma-24-45 were labeled with 4-(N-maleimido)benzophenone at the COOH and NH2 termini, respectively, and then cross-linked to alpha t. When the photoprobe was attached to the COOH terminus of the peptide, a specific high yield cross-linked product (80%) was formed between the peptide and alpha t GTP gamma S (guanosine 5'-O-(thiotriphosphate)). A lower yield of cross-linking (35%) was seen between the peptide and alpha t GDP. The site of cross-linking between Cys(ACM)Tyr-P gamma-24-45-Cys and alpha t GTP gamma S was localized to within alpha t-306-310 using a variety of chemical and proteolytic cleavages of the cross-linked product, analysis of the fragments with SDS-polyacrylamide gel electrophoresis, and matrix-assisted laser desorption ionization mass spectrometry.
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PMID:A site on transducin alpha-subunit of interaction with the polycationic region of cGMP phosphodiesterase inhibitory subunit. 822 88

Calmodulin (CaM), a calcium-binding protein, is present in human tumor tissues and in meningioma. Following a purification procedure using DEAE-cellulose and the polymeric resin 3520, the CaM content of tumor extracts was assayed using CaM-deficient phosphodiesterase (PDE). In the presence of low amounts of the extracts, a concentration dependent stimulation of PDE was observed. However, further addition of higher concentrations of the extract produced a marked inhibition of the CaM stimulation of PDE in 13 of 15 specimens. A wide range (2.44-51.31 units/1 mg tumor [wet weight]) of inhibitor concentration was noted. However, no detectable inhibitory activity of this magnitude was observed in normal human meningeal extracts. The final extracts showed no calcineurin-phosphatase activity in the presence of Ni++, a known activator of this phosphatase. SDS-polyacrylamide gel (10%) electrophoresis of the extracts revealed the typical calmodulin band at 17 kDa plus two additional bands with apparent molecular masses of 21 and 36 kDa respectively. These bands were not seen using normal meningeal extracts.
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PMID:Evidence for a calmodulin inhibitory substance(s) isolated from human meningiomas. 830 44

The specific activity of D-glyceraldehyde-3-phosphate (G3P) dehydrogenase (phosphorylating) (GPDH, EC 1.2.1.12) found in liver of induced hibernating jerboa (Jaculus orientalis) was 2-3-fold lower than in the euthermic animal. However, the comparative analysis of the soluble protein fraction of these tissues by SDS-PAGE and Western blotting showed no significant changes in the intensity of the 36 kDa protein band of the GPDH subunit. After using the same purification procedure, the GPDH from liver hibernating jerboa exhibited lower values for both apparent optimal temperature and specific activity than the enzyme from the euthermic animal. Similar non-linear Arrhenius plots were obtained, but the Ea values calculated for the GPDH from hibernating tissue were higher. Although in both purified enzyme preparations four isoelectric GPDH isoforms were resolved by chromatofocusing, those of hibernating liver exhibited more acidic pI values (pI 7.3-6.1) than the hepatic isoforms of euthermic animals (pI 8.7-8.1). However, all liver GPDH isoforms exhibited similar native and subunit molecular masses and cross-reacted with an antibody raised against muscle GPDH. The comparison of the kinetic parameters of both purified preparations and the main isoforms isolated from euthermic and hibernating tissues showed the decreased catalytic efficiency of hibernating enzyme being exclusively due to a lower Vmax for both substrates G3P and NAD+. Phosphodiesterase treatment of cell-free extracts increased GPDH activity in the case of hibernating liver only. The pI of the main isoform purified from this tissue, about 6.9, changed after this treatment to an alkaline value (pI 8.44) similar to those of the euthermic GPDH isoforms. Differential ultraviolet absorption spectra of these isoforms indicated that a substance absorbing at 260 nm, that was released by the phosphodiesterase digestion, was present in the enzyme of hibernating tissue. Incubation of purified GPDH with the NO-releasing agent sodium nitroprussite produced under conditions that promote mono-ADP-ribosylation a dramatic decrease of activity (up to 60%) of both euthermic and phosphodiesterase-treated hibernating preparations but only a marginal inhibition of the hibernating enzyme. These data suggest that the liver GPDH of hibernating jerboa exhibits a posttranslational covalent modification, being probably a mono-ADP-ribosylation. The resulting inhibition of enzyme activity could contribute to the wide depression of the glycolytic metabolic flow associated with mammalian hibernation.
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PMID:Evidence for a posttranslational covalent modification of liver glyceraldehyde-3-phosphate dehydrogenase in hibernating jerboa (Jaculus orientalis). 854 42

We have cloned two open reading frames (orf6 and orf8) from the Escherichia coli K-12 rfb region. The genes were expressed in E. coli under control of the T7lac promoter, producing large quantities of recombinant protein, most of which accumulated in insoluble inclusion bodies. Sufficient soluble protein was obtained, however, for use in a radiometric assay designed to detect UDP-galactopyranose mutase activity (the conversion of UDP-galactopyranose to UDP-galactofuranose). The assay is based upon high-pressure liquid chromatography separation of sugar phosphates released from both forms of UDP-galactose by phosphodiesterase treatment. The crude orf6 gene product converted UDP-[alpha-D-U-14C]-galactopyranose to a product which upon phosphodiesterase treatment gave a compound with a retention time identical to that of synthetic alpha-galactofuranose-1-phosphate. No mutase activity was detected in extracts from cells lacking the orf6 expression plasmid or from orf8-expressing cells. The orf6 gene product was purified by anion-exchange chromatography and hydrophobic interaction chromatography. Both the crude extract and the purified protein converted 6 to 9% of the UDP-galactopyranose to the furanose form. The enzyme was also shown to catalyze the reverse reaction; in this case an approximately 86% furanose-to-pyranose conversion was observed. These observations strongly suggest that orf6 encodes UDP-galactopyranose mutase (EC 5.4.99.9), and we propose that the gene be designated glf accordingly. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of purified UDP-galactopyranose mutase revealed one major band, and analysis by electrospray mass spectrometry indicated a single major species with a molecular weight of 42,960 +/- 8, in accordance with that calculated for the Glf protein. N-terminal sequencing revealed that the first 15 amino acids of the recombinant protein corresponded to those expected from the published sequence. UV-visible spectra of purified recombinant enzyme indicated that the protein contains a flavin cofactor, which we have identified as flavin adenine dinucleotide.
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PMID:Galactofuranose biosynthesis in Escherichia coli K-12: identification and cloning of UDP-galactopyranose mutase. 857 37

Cyclic inositol phosphohydrolase is a phosphodiesterase that cleaves the cyclic bond of cyclic inositol monophosphate. In 1990, Ross et al. (Ross, T. S., Tait, J. F., and Majerus, P. W. (1990) Science 248, 605-607) purified this enzyme from human placenta and reported that cyclic inositol phosphohydrolase is identical to annexin III. Independent confirmation of this finding has not been provided. The relative distribution of annexin III and cyclic inositol phosphohydrolase activity in rat kidney and spleen indicated that annexin III can be dissociated from cyclic inositol phosphohydrolase activity. Rat spleen contains large quantities of annexin III, but has very little cyclic inositol phosphohydrolase activity. In contrast, rat kidney, one of the richest sources of cyclic inositol phosphohydrolase activity, possesses very little (immunohistochemistry) or no (Western blot) annexin III. Similar to cytosol of human placenta, cytosol of guinea pig kidney contains both annexin III and cyclic inositol phosphohydrolase. On SDS-gel electrophoresis, guinea pig kidney annexin III has a slightly different mobility than the human placental annexin III. Human placental annexin III co-migrates with cyclic inositol phosphohydrolase on ion exchange chromatography, while guinea pig kidney annexin III is clearly dissociated from cyclic inositol phosphohydrolase on ion exchange chromatography. Both guinea pig kidney annexin III and human placental annexin III pellet with the addition of calcium and centrifugation, while cyclic inositol phosphohydrolase activity in both of these tissues remains in the supernatant. Our studies clearly show that cyclic inositol phosphohydrolase and annexin III are two different proteins.
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PMID:Dissociation of cyclic inositol phosphohydrolase activity from annexin III. 862 24

A secreted phosphodiesterase/alkaline phosphatase, APaseD, was purified from a culture of Bacillus subtilis JH646MS. Its phosphodiesterase activity was reminiscent of an APase isolated and characterized previously. Immunoassay and N-terminal sequencing showed the two proteins to be identical. Using the first 20 amino acids of the mature protein, a BLAST search of GenBank was used to find an homologous sequence. An exact match was found but in a putative non-coding region. It was hypothesized that there was a base pair deletion in the phoD gene. A DNA fragment internal to the coding region was generated by PCR using template DNA from a strain which produced APaseD. The PCR fragment was cloned and used to interrupt the gene. Western blot analysis of the parent and the mutated strains showed that APaseD was missing in the mutant. Resequencing of the gene revealed a larger ORF encoding a protein similar in size to the 49 kDa APaseD estimated by SDS-PAGE. The promoter was then cloned, sequenced and used in phoD-lacZ promoter fusions which showed that the gene was phosphate-starvation-induced and dependent on PhoP and PhoR for expression.
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PMID:A Bacillus subtilis secreted phosphodiesterase/alkaline phosphatase is the product of a Pho regulon gene, phoD. 876 Sep 16

A Zn(2+)-glycerophosphocholine cholinephosphodiesterase was purified with a specific activity of 4.6 mumole/min.mg protein from bovine brain membranes by procedures involving PI-PLC solubilization, concanavalin A affinity chromatography, CM-sephadex chromatography and Sephadex G-150 chromatography. Based on molecular weight determination gel chromatography and SDS polyacrylamide gel electrophoresis, the phosphodiesterase activity appears to be a dimeric protein (110 kDa) composed of two subunits with a molecular weight of approximately 54 kDa. The K(m) value for p-nitrophenylphosphocholine and the optimum pH were found to be 16 microM and pH 10.5, respectively. The phosphodiesterase was inhibited by Cu2+, but not the other divalent metal ions. The activity of the apoenzyme was remarkably activated by Co2+ or Zn2+, but not Mn2+ or Mg2+. In addition, the inactivation of the enzyme in glycine buffer was prevented by Mn2+ or Zn2+, but not Co2+ or Mg2. In a separate experiment, comparing properties of the purified and membrane-bound phosphodiesterases, the forms of two enzymes were quite similar except in stability. Both enzymes were more stable at pH 7.4 than pH 5 or 10. However, the membrane-bound enzyme was more stable than the soluble enzyme at all three pHs. These data suggest that the activity of the phosphodiesterase may be stabilized in-vivo.
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PMID:Properties of a Zn(2+)-glycerophosphocholine cholinephosphodiesterase from bovine brain membranes. 892 80

By means of CM-Sephadex C-25, DEAE-Sephadex A-50, Sephadex G-200, and Sephadex G-75 chromatographies, a lupus anticoagulant like protein (LALP) from Agkistrodon halys brevicaudus was purified. On SDS-PAGE, the purified LALP had a molecular weight of 25,500 daltons under non-reducing condition and 15,000 daltons under reducing condition. The isoelectric point was pH 5.6. Its N terminal amino acid sequencing revealed a mixture of 2 sequences: DCP(P/S)(D/G)WSSYEGH(C/R)(Q/K). It was devoid of phospholipase A, fibrino(geno)lytic, 5'-nucleotidase, L-amino acid oxidase, phosphomonoesterase, phosphodiesterase and thrombin-like activities, which were found in crude venom. In the presence of LALP, PT, aPTT, and dRVVT of human plasma were markedly prolonged and its effects were concentration-dependent but time-independent. The inhibitory effect of LALP on the plasma clotting time was enhanced by decreasing phospholipid concentration in TTI test. The individual clotting factor activity was not affected by LALP when higher dilutions of LALP-plasma mixture were used for assay. Russell's viper venom time was shortened when high phospholipid confirmatory reagent was used. Therefore, the protein has lupus anticoagulant property.
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PMID:Purification and characterization of lupus anticoagulant like protein from Agkistrodon halys brevicaudus venom. 897 23

The biotinylated probe, 3-azido-10-(4-(4-biotinyl-1-piperazinyl)butyl)phenothiazine, was used to examine the phenothiazine binding domains in calmodulin (CaM) by photolabeling. This phenothiazine, synthesized from 3-azido-10-(4-(1-piperazinyl)butyl)phenothiazine and d-biotinyl tosylate, inhibited the CaM-mediated activation of phosphodiesterase (PDE) with an I50 of 12.5 (+/- 2.8) microM. Photolabeling of CaM produced covalent adducts in excellent yield (32%) in a light- and Ca2+-dependent manner. Studies performed over a range of drug concentrations suggested a 2:1 stoichiometry for the binding of the phenothiazine probe to CaM. Limited trypsin digestion and purification of the resulting fragments by either SDS-PAGE or HPLC provided two principal phenothiazine-containing peptides. Amino acid composition and sequence analyses performed on these two peptides established that both the N- and C-terminal domains in CaM, particularly the regions amino terminal to Ca2+-binding loops 1 and 3, were modified by the photoactivated phenothiazine derivative. These data, particularly for the C-terminal domain, are in excellent agreement with the X-ray structure analysis of a 1:1 CaM-trifluoperazine complex.
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PMID:Synthesis and use of a biotinylated 3-azidophenothiazine to photolabel both amino- and carboxyl-terminal sites in calmodulin. 897 54


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