Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The concentrations of bases, nucleosides, and nucleosides mono-, di- and tri-phosphate are compared for about 600 published values. The data are predominantly from mammalian cells and fluids. For the most important ribonucleotides, average concentrations +/- SD (microM) are: ATP, 3,152 +/- 1,698; GTP, 468 +/- 224; UTP, 567 +/- 460 and CTP, 278 +/- 242. For deoxynucleosides-triphosphate (dNTP), the concentrations in dividing cells are: dATP, 24 +/- 22; dGTP, 5.2 +/- 4.5; dCTP, 29 +/- 19 and dTTP 37 +/- 30. By comparison, dUTP is usually about 0.2 microM. For the 4 dNTPs, tumor cells have concentrations of 6-11 fold over normal cells, and for the 4 NTPs, tumor cells also have concentrations 1.2-5 fold over the normal cells. By comparison, the concentrations of NTPs are significantly lower in various types of blood cells. The average concentration of bases and nucleosides in plasma and other extracellular fluids is generally in the range of 0.4-6 microM; these values are usually lower than corresponding intracellular concentrations. For phosphate compounds, average cellular concentrations are: Pi, 4400; ribose-1-P, 55; ribose-5-P, 70 and P-ribose-PP, 9.0. The metal ion magnesium, important for coordinating phosphates in nucleotides, has values (mM) of: free Mg2+, 1.1; complexed-Mg, 8.0. Consideration of experiments on the intracellular compartmentation of nucleotides shows support for this process between the cytoplasm and mitochondria, but not between the cytoplasm and the nucleus.
Mol Cell Biochem 1994 Nov 09
PMID:Physiological concentrations of purines and pyrimidines. 787 93

The production of transgenic animals from ungulate species is an inefficient and expensive procedure. The development of selection methods to identify the small number of transgenic preimplantation embryos produced following DNA microinjection of one-cell embryos would greatly reduce both the cost and effort of these procedures. This study has examined the fate of the ovine beta-lactoglobulin-human alpha 1-antitrypsin (AATB) minigene construct or a subfragment of this following microinjection into one-cell mouse embryos. It has examined two PCR-based methods that were designed to identify a biochemical difference between microinjected DNA constructs to select preimplantation stage embryos in which chromosomal integration of exogenous DNA has occurred. The two methods involved the modification of the AATB DNA construct either by dam methylation or the substitution of dTTP by dUTP. The dam-sensitive DNA endonuclease DpnI, that was used to digest nonintegrated AATB sequences at sites located between PCR oligonucleotide sequences, was found to interfere with the activity of the subsequent PCR reaction. Analyses of the fate of dUTP-DNA indicated that either repair or replication of microinjected DNA interfered with the ability to distinguish between integrated and nonintegrated DNA constructs in the mid-preimplantation stage embryo. The distribution of microinjected AATB DNA between the blastomeres of individual four and eight-cell stage embryos was also examined by the PCR reaction. Microinjected DNA was not found to be evenly distributed between all the blastomeres of individual embryos.
Mol Reprod Dev 1994 Dec
PMID:Use of PCR-based methods for selection of integrated transgenes in preimplantation embryos. 789 87

We have undertaken to characterize the role of cytoplasmic 5'-nucleotidase (EC 3.1.3.5) in the phosphorylation of the anti-herpes simplex virus and anti-human cytomegalovirus agent ganciclovir (GCV) in MOLT-4 cells, a human T cell line adapted to grow in suspension culture. The rate of formation of GCV triphosphate was found to be approximately doubled by preincubation of nontransfected MOLT-4 cells with agents that cause the accumulation of IMP, such as ribavirin (20 microM) and mycophenolic acid (1 microM), and the reaction rate was found to be unaffected by high levels of thymidine (100 microM). With herpes simplex virus-1 thymidine kinase (HStk) gene-transduced MOLT-4 cells, the rate of GCV phosphorylation was approximately 40-fold faster than that in uninfected cells and, in marked contrast to uninfected cells, the reaction was significantly inhibited both by IMP dehydrogenase inhibitors and by thymidine. These latter effects appear to be the result of 1) the accumulation of high levels of dTTP in IMP dehydrogenase inhibitor-treated cells, with consequent feedback inhibition of HStk, and 2) direct competitive substrate inhibition by thymidine of the HStk-catalyzed phosphorylation of GCV. Thus, agents that enhance 5'-nucleotidase-catalyzed phosphorylation of GCV in uninfected cells do not play a similar role in HStk-transfected cells, a consequence of the quantitative predominance of the viral thymidine kinase-catalyzed reaction over that attributable to endogenous cytoplasmic 5'-nucleotidase.
Mol Pharmacol 1994 Apr
PMID:Effects of IMP dehydrogenase inhibitors on the phosphorylation of ganciclovir in MOLT-4 cells before and after herpes simplex virus thymidine kinase gene transduction. 791 Mar 73

The effects of hydroxyurea (HU), an inhibitor of ribonucleotide reductase, on the replication of human immunodeficiency virus type 1 (HIV-1) in activated peripheral blood mononuclear cells were studied. The inhibition of HIV-1 replication by HU alone was dose dependent, with a 90% inhibitory concentration of 0.4 mM, a plasma concentration tolerated by patients with oncological diseases. HU at lower concentrations (< 0.1 mM) was found to potentiate the antiviral activity of 2',3'-dideoxyinosine (ddl), 3'-azido-2',3'- dideoxythymidine, and 2',3'-dideoxycytidine against HIV-1, with the potentiation being ddl greater than 3'-azido-2',3'- dideoxythymidine = 2',3'-dideoxycytidine. In the presence of 0.1 mM HU, the 90% inhibitory concentration of ddl was reduced by 6-fold in activated peripheral blood mononuclear cells. The potentiating effect of HU on ddl action was time dependent, with the greatest inhibition of HIV-1 growth being seen when HU was present during and after virus adsorption, i.e., apparently coinciding with the time of proviral DNA synthesis. A brief incubation of activated cells with HU and ddl at low concentrations before virus exposure reduced p24 production by > 50%. Analyses using high performance liquid chromatography and enzymatic assays suggested that the greater degree of potentiation by HU of the action of ddl, compared with the other dideoxynucleosides, is due to the more effective inhibition by HU of dATP synthesis, compared with the synthesis of the other deoxynucleoside triphosphates (dGTP, dTTP, and dCTP). The present study suggests that, for appropriate agents, pharmacological reduction of deoxynucleoside triphosphate levels represents a potential therapeutic approach for inhibition of HIV-1 replication.
Mol Pharmacol 1994 Oct
PMID:Anti-human immunodeficiency virus type 1 activity of hydroxyurea in combination with 2',3'-dideoxynucleosides. 796 58

Two acidic chitinase isoforms, SP1 and SP2, have been purified to homogeneity from leaves of sugar beet (Beta vulgaris) infected with Cercospora beticola. SP1 and SP2 are extracellular proteins with an apparent molecular mass of 35 kDa and an approximate pI of 4.2. Since the only major difference was slightly diverging M(r)'s, only the SP2 chitinase was further characterized. Partial amino acid sequence data for SP2 was used to generate a polymerase chain reaction (PCR) clone employed for the isolation of a cDNA clone encoding SP2. SP2 exhibits significant structural identity with the class IV chitinases from sugar beet, rapeseed, bean and maize, but differs from the other members of this class in having a longer hinge region, comprising 22 amino acid residues, with a repeated 'TTP' motif. Western blotting analyses, using antibody raised against SP2, demonstrated an induction of SP protein during infection with C. beticola. The induction was very local, with high protein accumulation found close to the infection site only. Amino acid compositional analysis of SP2 revealed that five out of fourteen prolines are hydroxylated. No glucosamine or galactosamine residues are present. Evidence was obtained that SP2 is glycosylated with a limited number (< or = 7) of xylose residues: (1) SP2 was stained with the periodic acid-Schiff (PAS) reagent, (2) electrospray mass spectrometry on SP2 gave a series of M(r)'s with a consistent increase between two molecular masses of 132 Da, (3) SP2 was recognized by an antibody specific for beta-1,4-D-xylopyranose. The vacuolar class I chitinases A and B in tobacco have recently been shown to comprise a new class of hydroxyproline-containing proteins (Sticher et al., Science 257 (1992) 655-657). The SP2 chitinase differs from these in being glycosylated and, thus, represents a novel type of hydroxyproline-containing glycoproteins in plants.
Plant Mol Biol 1994 May
PMID:A hydroxyproline-containing class IV chitinase of sugar beet is glycosylated with xylose. 801 73

It has been reported that thymidylate synthase (TS) is a component of a multienzyme complex associated with DNA replication based on observations that enzyme activity was decreased when cells were treated with various DNA synthesis inhibitors (Plucinski, T. M., Fager, R. S., and Reddy, G. P. V. (1990) Mol. Pharmacol. 38, 114-120). The veracity of the TS assay (known as the tritium release assay) employed in these experiments may be compromised, however, because it requires the S phase-specific enzyme thymidine kinase (TK) to phosphorylate the substrate [5-3H]dUrd. In our study, this problem was further illustrated as the phosphorylated products of [14C]dCyd and [6-3H]dUrd were simultaneously quantitated to determine the activities of TS, TK, and dCyd kinase in intact CCRF-CEM cells. TS and dCyd kinase were unaffected by aphidicolin, hydroxyurea, and 1-beta-D-arabinofuranosylcytosine, whereas TK was strongly inhibited by these agents. Elevation of the cellular dTTP pool that accompanied drug treatment was not the primary mechanism affecting TK activity because incubation of cells with dCyd elevated the dTTP pool to similar levels, but did not inhibit TK to the same extent as did the drugs. Furthermore, after cells were washed from aphidicolin, [6-3H]dCyd incorporation, which primarily labels dTMP in DNA, proceeded at a linear rate, whereas a lag period of 15 min was observed before [3H]dThd was incorporated at a linear rate. These results suggest that TK activity is affected by more than one mechanism in intact cells. Because the activities of dCyd kinase and dCMP deaminase do not fluctuate as much as that of TK in response to changes in DNA synthesis activity and cell cycle, dCyd incorporation appears to be a more reliable assay of TS in intact cells than does dUrd incorporation. Our findings also imply that [3H]dThd incorporation assays may overestimate inhibition of DNA synthesis.
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PMID:Regulation of thymidine kinase and thymidylate synthase in intact human lymphoblast CCRF-CEM cells. 822 47

Recombinant interferon-alpha (IFN) enhances the cytotoxic effects of the fluorinated pyrimidine, 5-fluorouracil (5FU), against two human colon cancer cell lines. The aspartate transcarbamylase (ATCase) inhibitor, N-(phosphonacetyl)-L-aspartate (PALA), was studied in combination with 5FU/IFN to determine whether further anti-pyrimidine effects would result in greater cytotoxicity. By median effects analysis PALA synergistically augmented the cytotoxic effects of 5FU/IFN against both human colon cancer cell lines. This occurred in the absence of any effects of 5FU/IFN on ATCase and without further potentiation of the PALA-mediated inhibition of ATCase. To explore the mechanism by which this interaction occurred, detailed studies of pools of dNTPs were performed. Both 5FU/IFN and PALA/5FU/IFN treatments resulted in early (2-8 hr) depletion of pools of dTTP, but no effects on pools of dCTP. PALA had no effect on dTTP pools either alone or in the combination. In contrast, both PALA and PALA/5FU/IFN treatments resulted in later (12-24 hr) depletion of pools of dCTP. 5FU/IFN treatment had no effect on these pools. When pools of dCTP and dTTP were repleted by treatment with cytidine or thymidine, 20 microM, however, there was only partial reversal of cytotoxicity induced by 5FU/IFN + PALA, suggesting that the synergy observed did not result solely from a sequential anti-pyrimidine effect. The incorporation of 5FU into RNA was also studied; PALA enhanced the incorporation of [6-3H]5FU into RNA by 83-150%, but not into DNA, suggesting an alternative mechanism of drug interaction.
Mol Pharmacol 1993 Nov
PMID:N-(phosphonacetyl)-L-aspartate synergistically enhances the cytotoxicity of 5-fluorouracil/interferon-alpha-2a against human colon cancer cell lines. 824 10

Wheat germ DNA polymerase A, a gamma-like enzyme, recognized efficiently natural and synthetic RNA templates, resembling a retroviral reverse transcriptase (P. Laquel et al., Biochim Biophys Acta 1048 (1990): 139-148). Ammonium-21-tungsto-9-antimoniate (HPA-23), an antiviral drug, inhibited the DNA polymerase A activities, independently of the template primers used, i.e. activated DNA or polyriboadenylic acid oligodeoxythymidylate (poly(rA)-oligo(dT)). The inhibition observed in the poly(rA)-oligo(dT)-directed DNA polymerase A activity occurred in the presence of either Mg2+ or Mn2+ as divalent cation, and also with the 2'-fluoro analogue of poly(rA) as template. HPA-23 was a non-competitive inhibitor with respect to TTP, activated DNA, poly(rA)-oligo(dT), and poly(dAfl)-oligo(dT). A preincubation study showed a reversible HPA-23 binding to DNA polymerase A, in the presence of poly(rA)-oligo(dT) as the template primer.
Plant Mol Biol 1993 Dec
PMID:Inhibition of the wheat germ DNA polymerase A activity by the antiviral drug HPA-23. 826 Jun 25

We have previously reported the purification of a 37 KDa platelet agglutinating protein (PAP p37) from the plasma of a patient with thrombotic thrombocytopenic purpura and have shown that it is present in a subset of TTP patients, but absent in normal subjects. In this study, we would like to report some of the physico-chemical and immunological properties of this protein. The native molecular weight of PAP p37 from gel filtration was found to be 36,000, which is in agreement with denatured molecular weight (37,000), determined by SDS--polyacrylamide gel electrophoresis under both reducing and non-reducing conditions. The values of Stoke's radius (25A), diffusion coefficient (8.59 x 10(-7)cm2/s) and frictional ratio (1.13), determined by molecular sieve chromatography, suggest that the native protein is compact and globular. The purified protein has an S20,w of 3.5s. Preliminary carbohydrate analysis suggested that p37 is a glycoprotein and contained about 11% neutral sugars and 6.6% sialic acid. Amino acid analysis indicated that the protein is relatively rich in aspartate and serine and has low cysteine, methionine and tryptophan contents. In dot immunobinding ELISA assay, PAP p37 did not react with antibodies to thrombospondin, fibrinogen, fibronectin, plasminogen and von Willebrand factor. Our results suggest that PAP p37 is a single polypeptide compact and globular glycoprotein and is immunologically not related to the aforementioned proteins.
Biochem Mol Biol Int 1993 Jun
PMID:Characterization of platelet agglutinating protein p37 purified from the plasma of a patient with thrombotic thrombocytopenic purpura. 836 16

A one-step polymerase chain reaction (PCR) was used to synthesize a digoxigenin-labelled probe, 176 bp long, for the detection of human polyomavirus BK (BKV). A 104 bp-long digoxigenin-labelled probe was generated by 'nested' PCR for the detection of human parvovirus B19 (virus B19). In both cases the whole viral genome was used as template. Different amounts of template as well as different percentages of dTTP substituted by digoxigenin-dUTP (dig-dUTP) in the reaction mixture were employed in order to determine the optimum conditions for the labelled probe synthesis. The sensitivity and the specificity of these PCR-produced probes, together with the simplicity and the reduced time scale of the procedure, suggest the potential of this technique as an additional method for preparing non-radioactive molecular probes for routine diagnosis of viral infections.
Mol Cell Probes 1993 Feb
PMID:Polymerase chain reaction for synthesis of digoxigenin-labelled DNA probe: application to parvovirus B19 and to polyomavirus BK. 838 14


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