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 products derived from the degradation of the sixteen possible diribonucleoside monophosphates (NpN') by Fusarium phosphodiesterase-phosphomonoesterase were analyzed by means of thin layer chromatography. The analysis showed that NpN' was first cleaved into nucleoside N and 5'-nucleotide pN', which was then dephosphorylated to yield nucleoside N'. The dephosphorylation was fast when N' was adenosine or cytidine but slow when N' was guanosine or uridine. The cleavage reaction was followed by measuring the increase of absorbance due to hyperchromicity, and the kinetic constants, Km and kcat, were determined for the sixteen dinucleoside phosphates. The Km value was higher, for a given N, when N' was a pyrimidine nucleoside than when N' was a purine nucleoside. For a given N', uridine as N gave the highest Km value and adenosine gave the lowest one. The kcat value was the highest, for a given N, when N' was cytidine. For a given N', uridine as N gave by far the lowest kcat value. These results can be interpreted in terms of two binding sites on the enzyme with different base preferences. Comparison of kcat/Km values suggested that the base of nucleoside N plays an important role in determining whether a dinucleoside phosphate is a good substrate of the enzyme. The dinucleoside phosphates with uridine as N were found to be particularly poor substrates of the enzyme.
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PMID:Mode of hydrolysis of diribonucleoside monophosphates by phosphodiesterase-phosphomonoesterase of Fusarium moniliforme. 627 68

We have searched for the presence of branching in the chromosomal polymer poly(ADP-ribose) as it occurs in vivo. Treatment of the polymer with phosphodiesterase asnd phosphomonoesterase results in the conversion of internal residues to the nucleoside ribosyladenosine and the conversion of points of branching to diribosyladenosine. We have detected diribosyladenosine in digests of the polymer derived from carcinogen-treated SV40 virus-formed 3T3 cells and in normal rat liver, kidney, and spleen. The frequency of residues involved in branching varied from 0.8 to 1.6 mole % over a 50-fold range of total levels of poly(ADP-ribose). Thus, branching seems to be a general feature of poly(ADP-ribose) as it occurs in vivo.
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PMID:Poly(ADP-ribose) has a branched structure in vivo. 627 56

1. A new assay procedure has been devised for measurement of the Ca(2+)-activated polyphosphoinositide phosphodiesterase (phosphatidylinositol polyphosphate phosphodiesterase) activity of erythrocyte ghosts. The ghosts are prepared from cells previously incubated with [(32)P]P(i). They are incubated under appropriate conditions for activation of the phosphodiesterase and the released (32)P-labelled inositol bisphosphate and inositol trisphosphate are separated by anion-exchange chromatography on small columns of Dowex-1 (formate form). When necessary, phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate can be deacylated and the released phosphodiesters separated on the same columns. 2. The release of both inositol bisphosphate and inositol trisphosphate was rapid in human ghosts, with half of the labelled membrane-bound phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate broken down in only a few minutes in the presence of 0.5mm-Ca(2+). For both esters, optimum rates of release were seen at pH6.8-6.9. Mg(2+) did not provoke release of either ester. 3. Ca(2+) provoked rapid polyphosphoinositide breakdown in rabbit erythrocyte ghosts and a slower breakdown in rat ghosts. Erythrocyte ghosts from pig or ox showed no release of inositol phosphates when exposed to Ca(2+). 4. In the presence of Mg(2+), the inositol trisphosphate released from phosphatidylinositol 4,5-bisphosphate was rapidly converted into inositol bisphosphate by phosphomonoesterase activity. 5. Neomycin, an aminoglycoside antibiotic that interacts with polyphosphoinositides, inhibited the breakdown of both phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate, with the latter process being appreciably more sensitive to the drug. Phenylmethanesulphonyl fluoride, an inhibitor of serine esterases that is said to inhibit phosphatidylinositol phosphodiesterase, had no effect on the activity of the erythrocyte polyphosphoinositide phosphodiesterase. 6. These observations are consistent with the notion that human, and probably rabbit and rat, erythrocyte membranes possess a single polyphosphoinositide phosphodiesterase that is activated by Ca(2+) and that attacks phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate with equal facility. Inhibition of this activity by neomycin seems likely to be due to interactions between neomycin and the polyphosphoinositides, with the greater inhibition of phosphatidylinositol 4,5-bisphosphate breakdown consistent with the greater affinity of the drug for this lipid. In addition, erythrocyte membranes possess Mg(2+)-dependent phosphomonoesterase that converts inositol 1,4,5-triphosphate into inositol bisphosphate.
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PMID:The polyphosphoinositide phosphodiesterase of erythrocyte membranes. 627 38

The metabolism of inositol phospholipids of the erythrocyte membrane was compared in normotensive Wistar-Kyoto (WKY), spontaneously hypertensive (SHR), and stroke-prone SHR (SHR-SP) rats. This was performed on isolated ghost membranes by measuring the incorporation of 32P from [ gamma-32P ] adenosine triphosphate (ATP) into the diphosphoinositides (DPI) and the triphosphoinositides (TPI) which were the only 32P-labeled phospholipids. 32P-labeling of TPI was altered in adult and 3-week-old SHR as well as in SHR-SP compared to WKY controls; the radioactivity associated with TPI in hypertensive rats was about 30% lower than that associated with TPI in age-matched normotensive controls. By contrast, the radioactivity associated with DPI was similar in both hypertensive and normotensive rats. Measurement of the phosphoinositide distribution in both SHR and WKY indicates that the change observed in 32P-TPI could not be accounted for by a reduced phosphatidylinositol content in SHR membrane. Measurement of the Mg2+-activated TPI-phosphomonoesterase and of the Ca2+-activated polyphosphoinositide phosphodiesterase activities did not show any significant difference between SHR and WKY. It thus appears that the altered phosphoinositide metabolism observed in hypertensive rats was a consequence of some alteration in the activity of kinases which are responsible for the conversion of phosphatidylinositol into DPI and TPI. These results also suggest that the defect in phosphoinositide metabolism observed in genetically hypertensive rats was not a consequence of the blood pressure elevation and could be related to the pathogenesis of hypertension.
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PMID:Altered turnover of polyphosphoinositides in the erythrocyte membrane of the spontaneously hypertensive rat. 630 31

The properties of a teichoic acid degrading enzyme (teichoicase) isolated from Bacillus subtilis Marburg are described. The purified enzyme showed phosphodiesterase activity but not phosphomonoesterase activity, and it had an absolute substrate specificity for alpha-glucosylated glycerol teichoic acid, the endogenous cell wall teichoic acid of the enzyme-producing cell. The substrate was degraded by an exo-mechanism yielding the monomer alpha-D-glucose 1 leads to 2 (sn)glycero-3-phosphate. When B. subtilis Marburg was grown in a rich medium, enzyme activity was detected in extracts from sporulating cells. Teichoicase activity was present in a mutant blocked in stage II of the sporulation process but was absent in a mutant blocked in stage O. It was concluded that teichoicase is active on enzyme-producing cells since the reaction product could be detected in their culture supernatant. Attempts to demonstrate analogous enzyme activity in other Bacillus strains failed. The enzyme could be used for the rapid detection of alpha-glucosylated glycerol teichoic acid and for the controlled alteration of native bacterial cell surfaces exhibiting the appropriate structure.
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PMID:Teichoicase from Bacillus subtilis Marburg. 630 14

Like many amphiphilic cationic drugs, aminoglycosides are able to produce phospholipidosis, mainly by inhibiting enzymes involved in phospholipid metabolism. Phosphoinositides have been suggested to function as receptors for aminoglycosides. Therefore, we investigated the influence of these drugs upon phosphoinositide metabolism by measuring the 32P-incorporation into the polyphosphoinositides, using the rat erythrocyte membrane as a model. Depending upon the experimental conditions, neomycin induced a decrease and/or an increase in the 32P-labeling of triphosphoinositides (TPI) and of diphosphoinositides (DPI), respectively. These variations were rapid and depended upon the drug concentration. At 0.3 mM, neomycin reversed the distribution of radioactivities associated with DPI and TPI without modifying the total radioactivity incorporated. This drug concentration altered neither the Mg++-activated TPI-specific phosphomonoesterase activity nor the Ca++-activated polyphosphoinositide phosphodiesterase activity. It appears likely that the drug inhibits the DPI-kinase activity, by interacting with DPI and thereby lowering the substrate availability. Over the range of concentrations studied (up to 1-2 mM), gentamicin, kanamycin and dibekacin behave as neomycin. However, their effects could be observed only at drug concentrations higher than those of neomycin. By contrast, streptomycin and amikacin did not alter the 32P-labeling of TPI and of DPI. The order of potency of aminoglycosides for the impairment of the phosphoinositide interconversion was neomycin, gentamicin, dibekacin, kanamycin. A possible relationship between the toxicity of aminoglycosides and their capacity to impair the phosphoinositide metabolism is discussed.
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PMID:Impairment of membrane phosphoinositide metabolism by aminoglycoside antibiotics: streptomycin, amikacin, kanamycin, dibekacin, gentamicin and neomycin. 631 2

Four isoenzymes of phosphodiesterase were identified in Trimeresurus flavoviridis venom. A rapid and highly reproducible column chromatographic procedure on CM-Sephadex C-25, QAE-Sephadex A-25 and Sephadex G-100 was developed for the purification of these isoenzymes with a yield of 83%. All four isoenzymes are metalloglycoproteins having negligible amounts of phosphomonoesterase activity.
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PMID:Rapid method for separation and purification of four isoenzymes of phosphodiesterase from Trimeresurus flavoviridis (Habu snake) venom. 633 Jan 40

Two new extracellular nucleases, nucleases SM1 and SM2, were purified from the culture fluid of S. marcescens kums 3958, a fresh clinical isolate. The purification was carried out by the following steps; ammonium sulfate precipitation, and DEAE-cellulose and Sephadex G-100 column chromatography. At the final step, nucleases SM1 and SM2 were purified about 3,700- and 1,000-fold, respectively. They were free from phosphomonoesterase and phosphodiesterase activities. The pIs were 8.1 and 7.5 for nucleases SM1 and SM2, respectively. The molecular weight was estimated to be 35,000 for both enzymes by SDS-polyacrylamide disc gel electrophoresis. The results of amino acid analyses showed that both the threonine and serine contents were higher in nuclease SM2 than in SM1. Furthermore, nuclease SM1 was more stable than nuclease SM2 at 4 degrees C. The other properties of the two enzymes were similar; pH optimum (8.0), Mg2+ or Mn2+ for activation, and inhibition by chemical reagents such as EDTA and pyrophosphate. No significant difference was found in base specificity between nucleases SM1 and SM2. Both enzymes specifically degraded double-stranded homopolymers, especially poly(I). poly(C), as well as yeast RNA and calf thymus DNA. They hardly degraded, however, single-stranded homopolymers such as poly(dA), poly(G), and poly(U).
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PMID:Isolation and characterization of nucleases from a clinical isolate of Serratia marcescens kums 3958. 635 Feb 76

Screening of several fungal cultures resulted in the selection of an isolate of Aspergillus candidus which produced a considerable around of RNa-degrading enzyme in both surface and submerged methods of cultivation. The conditions for the assay of the RNAase were standardized at pH 4.5, 55 degrees C and using 0.25% yeast RNA as substrate. The enzyme was stable at pH 5.2. EDTA was found to activate the enzyme slightly. at temperatures 50-60 degrees C there was considerable loss in enzyme activity which was traced to the presence of a contaminating protease which presumably degraded the RNAase optimally at this temperature. The protease could be preferentially inactivated at or above 75 degrees C. The crude enzyme, in addition to RNAase was found to possess DNAase, nonspecific phosphodiesterase and 3'- and 5'-phosphomonoesterase activities.
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PMID:Standardization of assay procedure and some properties of ribonuclease from Aspergillus candidus. 679 71

DNases A1 and A2 have been purified to homogeneity from the hepatopancreas of Achatina fulica by a series of steps: acetate buffer extraction, ammonium sulfate precipitation and column chromatography on hydroxylapatite, phosphocellulose, Blue-Sepharose, and poly(A)-Sepharose. The purified enzymes are free of acidic phosphomonoesterase, phosphodiesterase, and RNase activities. They are slightly acidic glycoproteins with identical isoelectric point (6.90). On 0.1% SDS gel electrophoresis, DNase A2 had a molecular weight of 30,000 when dissolved in 1% SDS, but it had molecular weights of 17,500, 8,000, and 4,800 when dissolved in 1% SDS and 1% 2-mercaptoethanol. This was evidence that the enzyme consists of three different subunits joined by interchain disulfide bonds. DNases A1 and A2 are endonucleases working at acidic pH (3.5--6.0) and do not require divalent cations for their activities. The enzymes degrade poly(dA) 5 times faster and poly(dT) 3 times faster than heat-denatured DNA under optimal conditions but do not appreciably digest poly(dG) and poly(dC). We developed an analytical procedure for oligodeoxynucleotides by high-performance liquid chromatography. The phosphomonoester end group and the mode of degradation were examined by the method. The termini produced by the enzymes have 3'-phosphoryl and 5'-hydroxy end groups. The products of exhaustive hydrolysis contain di-, tri-, tetra-, and pentanucleotides and mononucleotide was barely detected. The hydrolyzing activities of DNases A1 and A2 are stimulated by polyamines such as spermine, spermidine, and putrescine, but are inhibited by synthetic polynucleotides and various drugs. Adenosine deaminase highly active on oligoadenylic acids was found in a crude DNase A fraction. The enzyme preparation has higher activity on 3'-adenylic acid than on 5'-adenylic acid. The first adenosine residue of oligoadenylic acids was deaminated considerably more rapidly than the second or succeeding ones.
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PMID:DNase A, a poly(dA) and poly(dT)-specific deoxyribonuclease from Achatina fulica. Purification and characterization. 733 15


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