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)

Isoenzyme V of 5'-nucleotide phosphodiesterase (5'-NPD-V) is present in the peripheral sera of patients with hepatic metastases. A total of 122 patients underwent prospective serologic analysis followed by operation for primary tumors of the gastrointestinal tract and careful evaluation of the liver. A positive 5'-NPD-V assay was found in fifty-nine of sixty patients with liver metastases. A negative 5'-NPD-V assay was found in forty-three of sixty-two patients with no evidence of hepatic metastases. The accuracy of the test was 84 per cent, and the predictive value was 75 per cent. Serum 5'-NPD-V was abnormal significantly more frequently in patients with metastatic liver disease than were liver scans or carcinoembryonic antigen (CEA), alpha fetoprotein, serum glutamic oxalacetic transaminase (SGOT), and total serum bilirubin or serum alkaline phosphatase levels.
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PMID:Serum 5'-nucleotide phosphodiesterase as a predictor of hepatic metastases in gastrointestinal cancer. 21 45

Herpes simplex virus (HSV) DNA polymerase was isolated on a large-scale from African green monkey kidney cells infected with HSV type 1 (HSV-1) strain Angelotti. After DNA-cellulose chromatography the enzyme showed a specific activity of 48,000 units/mg protein. Three major single polypeptides with molecular weights of 144,000, 74,000 and 29,000 were copurified with the enzyme activity at the DNA-cellulose ste. By its chromatographic behavior and by template studies, the HSV DNA polymerase activity was clearly distinguishable from cellular alpha, beta and gamma DNA polymerase activities. Two exonucleolytic activities were found in the DNA-cellulose enzyme preparation. The main exonucleolytic activity, which degraded both single-stranded and double-stranded DNA to deoxynucleoside 5'-monophosphates, was separated by subsequent velocity sedimentation. The remaining exonucleolytic activity was not separable from the HSV DNA polymerase by several chromatographic steps and by velocity sedimentation at high ionic strength. This novel exonuclease and HSV DNA polymerase were equally sensitive both to phosphonoacetic acid and Zn2+ ions, inhibitors of the viral polymerase. Similar to the 3'-to-5'-exonuclease of procaryotic DNA polymerases and mammalian DNA polymerase delta, the HSV-polymerase-associated exonuclease catalyzed the removal of 3'-terminal nucleotides from the primer/template as well as the template-dependent conversion of deoxynucleoside triphosphates to monophosphates.
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PMID:Properties of herpes simplex virus DNA polymerase and characterization of its associated exonuclease activity. 22 46

Contact-inhibited 3T3 mouse fibroblast cells, in contrast to logarithmically growing 3T3 cells and SV-3T3 transformed cells, have increased levels of plasma membrane-bound phosphodiesterase (oligonucleotidase, E.C.3.1.4.19; nucleotide pyrophosphatase, E.C. 3.6.1.9) activity. The increase in enzyme, recorded as increased specific activity, is reversible, as evidenced by the return to normal values following dilution of confluent 3T2 cells and re-initiation of growth. Increased enzyme activity is induced again when the cells regain the confluent state. Transformed SV-3T3 cells can be induced to mimic the contact inhibited state, including increased plasma membrane phosphodiesterase activity, by exposure to a combination of: (i) agents that are known to induce increased intracellular cAMP levels and (ii) additions of purified 3T3 or SV-3T3 plasma membranes. Additions of either alone fails to induce the increase in membrane phosphodiesterase activity, although each alone can significantly suppress cell growth, as measured by incorporation of 3H amino acids. We suggest that the elevation of plasma membrane phosphodiesterase activity may serve as a measure of conversion to the contact-inhibited state in both normal cells and phenotypically reverted transformed cells.
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PMID:Increase in plasma membrane phosphodiesterase activity in contact-inhibited 3T3 cells and in phenotypically reverted SV-3T3 cells. 22 43

Isolated plasma membranes from mouse fibroblast lines 3T3 and its tranformant SV-3T3 contain a phosphodiesterase (oligonucleotidase, E.C. 3.1.4.19; nucleotide pyrophosphatase, E.C. 3.6.1.9) that splits capped and methylated messenger RNA obtained from both reovirus and vesicular stomatitis virus. The isolated membranes are free of demonstrable ribonuclease activity and split the mRNA to produce 7-methyl guanosine diphosphate as a product. With ATP as substrate for the phosphodiesterase enzyme, the product is AMP. Synthetic caps, AMP, ADP and ATP, but not cyclic AMP, can compete with the substrate p-nitrophenyl thymidilic acid. A possible regulatory role on messenger translation is proposed.
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PMID:Uncapping of viral messenger RNA by phosphodiesterase of fibroblast plasma membranes. 22 44

Serum phosphodiesterase I (PDE I) activity was determined in 13 control and 51 breast-cancer patients with various stages of disease. Patients with both localized and metastatic breast cancer had significantly elevated serum PDE I activity. The highest activity was seen in patients with liver metastases. A decline in serum PDE I activity was seen after surgical resection of all known disease.
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PMID:Serum phosphodiesterase I activity in breast cancer patients. 23 44

A homopolymer system has been developed to examine the digestion strategies of DNA exonucleases. Escherichia coli exonuclease I and lambda-exonuclease, are processive enzymes. However, T7 exonuclease, spleen exonuclease, E. coli exonuclease III, the 3' leads to 5'-exonuclease of T4 DNA polymerase, and both the 3' leads to 5' and the 5' leads to 3' activity of E. coli DNA polymerase I dissociate frequently from the substrate during the course of digestion. Regions of duplex DNA are a dissociation signal for exonuclease I.
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PMID:Processivity of DNA exonucleases. 33 8

This report describes the results of our initial enzymological characterization of a homogeneous preparation of DNA polymerase alpha that we have purified from cultured human KB cells. Although the enzyme is most reactive with duplex DNA substrates that contain short gaps (optimally activated) in incubations that require Mg2+, the polymerase possesses the intrinsic capacity to copy the initiated ribohomopolymer template, (A)-n, (dT)-200, at low rates in the presence of Mn2+. Because of the preponderance of DNA polymerase alpha in actively multiplying vertebrate cells, it is probable that this low level of activity comprises the majority of the ribopolymer copying activity that can be detected in crude tissue extracts. The presence of contaminating or associated deoxyribonuclease activities can be excluded from the purified enzyme to levels of 10(-4) to 10(-7) of the polymerase activity. The mechanism of polymerization on activated DNA under optimum conditions is moderately processive, with 11 +/- 5 nucleotides incorporated per polymerization cycle. The polymerase is unable to work at nicks or at short gaps of approximately 20 to 30 nucleotides in length, and it measures a surprisingly invariant effective template length on optimally activated DNA and on DNA molecules that have been gapped to varying extents with Escherichia coli exonuclease III. In the "Appendix" we present an amplification of the theoretical formulation of Bambara et al. (Bambara, R. A., Uyemura, D., and Choi, T. (1978) J. Biol. Chem. 253, 413--423) that permits the use of DNA polymerases with significant associated 3' leads to 5'-exonuclease activities for the accurate measurement of average template lengths (gap sizes) and titration of usable 3'-hydroxyl primer termini in gapped, duplex DNA substrates.
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PMID:Enzymological characterization of DNA polymerase alpha. Basic catalytic properties processivity, and gap utilization of the homogeneous enzyme from human KB cells. 44 99

Leukocyte extracts containing human transfer factor (TF) were fractionated by exclusion chromatography, and the active fraction (Sephadex G25, Fraction IIIa) was subjected to high pressure, reverse phase (HPRP) chromatography and enzymatic degradation. TF activity was assessed by the systemic transfer of dermal skin test reactivity from KLH-immunized donors to naive recipients. Preparative HPRP chromatography resolved Fraction IIIa into multiple chromophoric regions, two of which demonstrated transfer of KLH reactivity. Alkaline phosphatase treatment of Fraction IIIa converted the major ultraviolet-absorbing component, 5'-inosine monophosphate, to inosine and resulted in TF activity being restricted to one region. This HPRP region (R1A) contained less than 1% of the UV254 active material in Fraction IIIa but greater than 90% of the reactivity. The sensitivity of TF to pronase, proteinase K, phosphodiesterase I, and phosphodiesterase II was evaluated by inhibition of systemic transfer of KLH reactivity. Pronase and proteinase K destroyed systemic transfer activity and the pronase destruction could be inhibited with traysylol. Phosphodiesterase I, a 3' exonuclease, destroyed activity, whereas phosphodiesterase II, a 5' exonuclease, did not. The data are consistent with a phosphodiester-containing polypeptide in the structure of human TF for KLH reactivity.
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PMID:Human transfer factors: structural properties suggested by HPRP chromatography and enzymatic sensitivities. 44 71

DNA polymerase beta from mouse myeloma has been purified to near homogeneity, and its properties have been examined. The enzyme did not catalyze a detectable level of dNTP turnover, pyrophosphate exchange, pyrophosphorolysis, 3'-exonuclease degradation, or 5'-exonuclease degradation. Steady-state kinetic studies point to an ordered bibi mechanism for the polymerization reaction. Metal activation, which is required for polymerization, did not alter the Km for either the dNTP or the template--primer.
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PMID:Steady-state kinetics of mouse DNA polymerase beta. 46 81

The 30S nuclear RNP particles from rat liver have been shown to split the double-stranded- (ds) and single-stranded (ss) sequences of nuclear pre-mRNA. Experiments performed in vitro have demonstrated that 1) a 5'-exonuclease and an endonuclease specific for double-stranded pre-mRNA sequences exist in the 30S pre-mRNP particles; 2) in dsRNA monophosphorylated 5'-termini arose in the course of incubation with 30S RNP and most of the products remained double-stranded. The analysis of terminal pNp nucleotides revealed a relatively high ratio of pPyp in the cleaved dsRNA, whereas the nucleosides in 5'-terminal pNp of ssRNA showed nearly random distribution. Our results provide a possible explanation for the appearance of pNp termini during the processing of nuclear pre-mRNA of mammalian cells.
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PMID:Cleavage of pre-mRNA sequences by ribonucleases bound to nuclear RNP particles of rat liver. 73 82


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