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Results for “Deoxyadenosines”

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At least 37 records · Page 2Linked to original sources
PubMed1979

Deoxyadenosine inhibits DNA synthesis in cultured human fibroblasts.

The rate of DNA synthesis in cultured diploid fibroblasts, nonmalignant human cells, is decreased by 50 microM 2'-deoxyadenosine when adenosine deaminase is inhibited and 2'-deoxyadenosine is phosphorylated to dATP. No inhibiton of DNA synthesis occurs with 100 microM adenosine under identical conditions or with 50 microM deoxyadenosine when adenosine deaminase is not blocked. Inhibition of DNA synthesis may be an important link between adenosine deaminase deficiency and severe combined immunodeficiency if the tissue culture model is relevant to lymphocyte function in man.

Adenine↗
PubMed1978

A role for purine metabolism in the immune response: Adenosine-deaminase activity and deoxyadenosine catabolism.

We have investigated a new hypothesis for the association between adenosine deaminase (A.D.A.) deficiency and immunodeficiency--namely, that deoxyadenosine rather than adenosine (an equally effective A.D.A. substrate) is toxic to proliferating cells of lymphoid origin. This possibility was explored in mitogen-stimulated lymphocytes cultured with a potent A.D.A. inhibitor, E.H.N.A. (erythro-9[2-hydroxy-3-nonyl] adenine) to simulate A.D.A. deficiency. In this in-vitro system deoxyadenosine was inhibitory at much lower and more physiological concentrations (1 mumol/1), compared with adenosine (100 mumol/1).

Adenosine↗
PubMed1979

Inhibition of ribonucleic acid efflux from isolated SV40-3T3 cell nuclei by 3'-deoxyadenosine (cordycepin).

The effect of 3'-deoxyadenosine (cordycepin) on mRNA efflux from isolated SV40-3T3 cell nuclei has been studied and compared with its effect on the nucleoside triphosphatase activity in the isolated nuclear envelope. Inhibition of mRNA efflux occurs rapidly, but is dependent on the presence of ATP. Half-maximal inhibition occurs with 40 microM-cordycepin. The effect is not simulated by 2'-deoxyadenosine or by actinomycin D, and adenosine provides a substantial degree of protection against it. Cordycepin does not directly inhibit the nucleoside triphosphatase. The stimulation of this enzyme by poly(A) is not affected unless the poly(A) and cordycepin are incubated together with nuclear lysate in the presence of ATP; in this case the stimulation is significantly reduced. Possible interpretations of these results and their relevance for understanding the system in vivo for nucleo-cytoplasmic messenger transport are discussed.

Adenosine↗
PubMed1975

2'-Deoxyadenosine and A23187 as agents for inducing synchrony in the budding yeast, Kluyveromyces fragilis.

The effects of induction synchrony by 2'-deoxyadenosine and the ionophore A23187 were compared with selection synchrony methods in Kluyveromyces fragilis. 2'-Deoxyadenosine synchronizes nuclear division and this is followed by synchronous cell division, but DNA synthesis is not synchronized. The ionophore A23187 also induces synchronous nuclear division and synchronous cell division, but likewise does not synchronize DNA synthesis.

Anti-Bacterial Agents↗
PubMed1977

Deoxyadenosine metabolism and toxicity in cultured L5178Y cells.

The growth of cultured L5178Y cells is inhibited by relatively low concentrations fo deoxyadenosine in the presence of deoxycoformycin, an inhibitor of adenosine deaminase. Cell viability is reduced, presumably as a consequence of the induced state of unbalanced growth which is characterized by inhibition in DNA synthesis, accumulation of cells in G1 or early S phase, a continuation in RNA synthesis, and increasing cell volume. The intracellular concentrations of purine and pyrimidine ribonucleoside phosphates remain essentially unchanged. The significant changes in the intracellular deoxynucleoside triphosphate pools are an increase in deoxyadenosine triphosphate and a decrease in deoxycytidine triphosphate.

Adenosine Deaminase Inhibitors↗
PubMed1976

Influenza virus RNA's in the cytoplasm of chicken embryo cells treated with 3'-deoxyadenosine.

3'-Deoxyadenosine (75 to 100 mug/ml) permitted analysis of the cytoplasmic influencza virus-specific RNAs synthesized early in the replicative cycle-a phase that has hitherto been obscurred by host cell RNA synthesis. In addition, late in the cycle (6 to 8) complementary virus-specific RNA's were the predominantly labeled species, suggesting that higher concentrations of 3'-deoxyadenosine selectively inhibit influenza viral genome replication.

Animals↗
PubMed1975

2-Halo derivatives of 3'-acetamido-3'-deoxyadenosine.

9-(3-Acetamido-2,5-di-O-acetyl-3-deoxy-beta-D-ribofuranosyl)-2,6-dichloropurine (VI) prepared by the mercuric cyanide catalyzed reaction of 3-acetamido-2,5-di-O-acetyl-3-deoxy-D-ribofuranosyl chloride (III) with 2,6-dichloropurine, was converted by standard reactions to 3'-acetamido-2-chloro-3'-deoxyadenosine (VII) and 3'-acetamido-3'-deoxy-2-fluoroadenosine (X). The 2-chloroadenine nucleoside VII was not cytotoxic, but the 2-fluoroadenine nucleoside X was moderately so, and its cytotoxicity to a subline of H.Ep.-2 cells resistant to 2-fluoroadenine indicates that its activity is due to the intact nucleoside.

Acetamides↗
PubMed1979

Benzo(a)pyrene-7,8-dihydrodiol 9,10-oxide adenosine and deoxyadenosine adducts: structure and stereochemistry.

The structure and absolute stereoconfigurations of four adenosine adducts with (+/-)-7 alpha,8 beta-dihydroxy-9 beta, 10 beta-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (BPDE) and their deoxyadenosine analogs have been determined. They result from both cis and trans addition of the N6 amino group of ademine to the 10 position of both enantiomers of BDPE. This was determined from studies of the nuclear magnetic resonance spectra, mass spectra, and circular dichroism spectra, as well as from their pKa values and chemical reactivities.

Benzopyrenes↗
PubMed1975

Effect of cordycepin (3'-deoxyadenosine) on virus-specific RNA species synthesized in Newcastle disease virus-infected cells.

Cordycepin (3'-deoxyadenosine) has no effect on the size or relative proportions of Newcastle disease virus-specific 18-22S mRNA species nor on the amount or size of the polyadenylic acid associated with them. Cordycepin does, however, cause an inhibition of incorporation of [3H]uridine into 50S virus-specific RNA relative to 18-22S RNA. This inhibition is probably not a direct effect of the drug on the synthesis of 50S viral RNA. Like cycloheximide, another drug which inhibits 50S RNA accumulation in paramyxovirus-infected cells, cordycepin inhibits protein synthesis as measured by amino acid incorporation. It is likely that the inhibition of 50S RNA accumulation is a secondary effect of protein synthesis inhibition. This is supported by the finding that concentrations of cordycepin and cycloheximide, which inhibit protein synthesis to the same extent, have the same effect on the ratio of 50 to 18-22S virus-specific RNA.

Cell Line↗
PubMed1992

Model building of DNA/RNA triple helix containing L-deoxyadenosine.

A three-dimensional model of DNA/RNA triple helix that contains a poly(L-deoxyadenosine) (L-dA) chain is proposed based on computer-assisted model building and energy calculations. The model building was performed by a new method that systematically searches possible conformations of nucleotide units in the helical chains. Two possible orientations of sugar-phosphate chains, in which two homopyrimidine strands are parallel or antiparallel with each other, were considered in the systematic search. Several possible base-pairing models, in which there are one Watson-Crick base pair and one other base pair, were also considered. Many possible models selected by the systematic search were further refined through molecular mechanics calculation incorporating a helical boundary condition. The preferred model, which was selected on the basis of potential energy, was the one with Watson-Crick and Hoogsteen base pairs and with its two polypyrimidine chains in the antiparallel orientation. The model can explain the experimental observation that poly(L-dA) forms a stable triple helix with poly(uridylic acid) (U) but not with poly(deoxythymidylic acid) (dT).

DNA↗
PubMed1975

An extended Scatchard analysis for competitively bound ligands and its application to cyclic adenosine-3',5'-monophosphate and cyclic 5'-amido-5'-deoxyadenosine-3', 5'-monophosphate binding to beef skeletal muscle protein.

A method for determining the dissociation constants of ligands and ligand analogs is described. It is based on competition binding studies in the presence of an isotope-labeled, or otherwise measurable, ligand and suitable analog concentrations. The steps used are determination of (1) the maximal amount of radioactive ligand that can be bound, (2) the slopes and intercepts from Scatchard plots at different analog concentrations and (3) the values for the dissociation constants of radioactive ligand and ligand analog from replots of the reciprocals of the slopes and intercepts obtained from the Scatchard plots. Application of the method to a cyclic AMP-binding protein from beef muscle is demonstrated, yielding dissociation constants of 2.10-9 M for cyclic (3H) AMP and cyclic AMP, and 3.10-5 M for cyclic 5'-amido-5'-deoxyadenosine-3', 5'-monophosphate.

Amides↗
PubMed1978

Deoxyadenosine triphosphate as a potentially toxic metabolite in adenosine deaminase deficiency.

The inherited deficiency of adenosine deaminase (adenosine aminohydrolase; EC 3.5.4.4) activity in humans is associated with an immunodeficiency. Some of the immunodeficient and enzyme-deficient patients respond immunologically to periodic infusions of irradiated erythrocytes containing adenosine deaminase. It has been previously reported that erythrocytes and lymphocytes from immunodeficient ane enzyme-deficient children contained increased concentrations of ATP, and in the one child studied after erythrocyte infusion therapy, the intracellular level of ATP diminished. Using high-pressure liquid chromatography that resolves ATP and 2'-dATP, we have observed greater than 50-fold elevations of dATP in the erythrocytes of immunodeficient, adenosine deaminase-deficient patients but not in the erythrocytes of an immunocompetent adenosine deaminase-deficient patient. The erythrocyte dATP in two unrelated adenosine deaminase-deficient, immunodeficient patients disappeared after infusion of normal erythrocytes. We propose that deoxyadenosine, a substrate of adenosine deaminase, is the potentially toxic substrate in adenosine deaminase deficiency, and that the mediator of the toxic effect is dATP, a recognized potent inhibitor of ribonucleotide reductase.

Adenine↗
PubMed1976

Conformational analysis of a DNA triplet in aqueous solution. Thymidylyl-(3'-5')-thymidylyl-(3'-5')-2'-deoxyadenosine, d(T-T-A), studied by 1H nuclear magnetic resonance at 360 MHz.

The proton signals of a 50 mM solution of thymidylyl-(3'-5')-thymidylyl-(3'-5')-2'-deoxyadenosine, d(T-T-A), in 2H2O at 65 degrees C and p2H=7.4, were detected by nuclear magnetic resonance at 360 MHz. Complete assignment of the 21 ribose proton signals was achieved by extensive decoupling experiments and computer simulations. The coupling constant data show that the ribose rings prefer to adopt the S (2'-endo) conformation. The presence of a substantial amount of a right handed helical structure of the d(-T-A) fragment is indicated from chemical shift considerations. The molecule displays a high degree of conformational purity along the sugar-phosphate backbone.

DNA↗