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1.
Prikl Biokhim Mikrobiol ; 36(1): 8-12, 2000.
Artigo em Russo | MEDLINE | ID: mdl-10752076

RESUMO

The properties of the phosphatase present in the culture liquid of Spicaria violacea were investigated. Based on these results, a method for preparative dephosphorylation of calcium salts of 2'(3')-mononucleotides was proposed. A 96-98% yield was achieved at a substrate concentration of 100 mg/ml. Mild quantitative hydrolysis of RNA to nucleosides can be performed by RNA digestion to mononucleotides with Ca2+ followed by the proposed dephosphorylation procedure.


Assuntos
Monofosfato de Adenosina/metabolismo , Fungos/enzimologia , Monoéster Fosfórico Hidrolases/metabolismo , Estabilidade Enzimática , Proteínas Fúngicas/metabolismo , Fosforilação
2.
Nucleosides Nucleotides ; 18(4-5): 687-8, 1999.
Artigo em Inglês | MEDLINE | ID: mdl-10432666

RESUMO

Chemical and enzymatic methods were employed for the synthesis of the title compound, 2'F-Guo 7. High antiviral activity of 2'F-Guo was established in chick embryo cells infected with influenza virus FPV/Rostock/34 (H7N1) and herpes simplex virus (HSV) type I (1C strain).


Assuntos
Antivirais/síntese química , Antivirais/farmacologia , Desoxiguanosina/análogos & derivados , Animais , Embrião de Galinha , Desoxiguanosina/síntese química , Desoxiguanosina/farmacologia , Herpesvirus Humano 1/efeitos dos fármacos , Orthomyxoviridae/efeitos dos fármacos
3.
Prikl Biokhim Mikrobiol ; 31(5): 494-7, 1995.
Artigo em Russo | MEDLINE | ID: mdl-7491361

RESUMO

The influence of temperature and Ca2+ ions at different concentrations on the effectiveness of RNA precipitation from water-salt extract of baker yeast was studied. Our findings allowed us to propose a method for producing highly purified RNA by precipitation with 180 mM Ca2+ ions from hot yeast extracts (95 degrees C) after removal of the protein fraction that could be also precipitated with 20 mM Ca2+ at 90 degrees C. The purity and yields of RNA samples obtained in such a manner was of 98% and 56% relative to theoretical values, respectively.


Assuntos
Cálcio , RNA Fúngico/isolamento & purificação , Saccharomyces cerevisiae/genética , Precipitação Química , Temperatura Alta
4.
Prikl Biokhim Mikrobiol ; 31(3): 308-10, 1995.
Artigo em Russo | MEDLINE | ID: mdl-7638156

RESUMO

The use of barium salts of ribose 1-phosphate and 2-deoxyribose-1-phosphate as the donors of the carbohydrate part of the required nucleosides in the reaction of enzymatic glycosylation of heterocyclic bases was studied. It was shown that application of indicated substrates in the synthesis of modified nucleosides-ribothymidine and bromovinyldeoxyuridine, catalyzed by the nucleoside phosphorylases from Escherichia coli BM-11, leads to the 96-98% yield of required products even at an equimolar ratio of original pentose 1-phosphates and heterocyclic bases in the reaction mixtures.


Assuntos
Compostos de Bário/química , Bromodesoxiuridina/análogos & derivados , Pentosefosfatos/química , Pentosiltransferases/metabolismo , Uridina/análogos & derivados , Bromodesoxiuridina/metabolismo , Catálise , Escherichia coli/enzimologia , Fermentação , Glicosilação , Indicadores e Reagentes , Uridina/biossíntese
5.
Appl Microbiol Biotechnol ; 32(6): 658-61, 1990 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-1367439

RESUMO

Synthesis of 9-(beta-D-arabinofuranosyl)guanine (ara-G) from 1-(beta-D-arabinofuranosyl)cytosine (ara-C) and guanine, guanosine or 2'-deoxyguanosine (dG) by glutaraldehyde-treated Escherichia coli BM-11 cells is described. It is shown that the concentration of phosphate ions, molar ratio of substrates and pH of the reaction medium are factors affecting product yield. Under optimum conditions ara-G was produced in the reaction mixture in a yield of 63%-65% based on dG as the best source of guanine base. The yield of isolated ara-G was 48%-53%.


Assuntos
Arabinonucleosídeos/biossíntese , Escherichia coli/metabolismo , Arabinonucleosídeos/isolamento & purificação , Proteínas de Bactérias/metabolismo , Citarabina/metabolismo , Citosina Desaminase , Glutaral , Guanina/metabolismo , Nucleotídeos de Guanina/metabolismo , Nucleosídeo Desaminases/metabolismo , Purina-Núcleosídeo Fosforilase/metabolismo , Uridina Fosforilase/metabolismo
6.
Nucleic Acids Symp Ser ; (18): 137-40, 1987.
Artigo em Inglês | MEDLINE | ID: mdl-3122186

RESUMO

Substrate specificity of uridine and purine nucleoside phosphorylases of the whole cells of Escherichia coli BM-11 has been studied. Both enzymes reveal similar requirements to the structure and stereochemistry of uracil nucleosides and of the pentofuranose-1-phosphates, respectively, viz, a) modifications at C-3' decreased the substrate activity to a greater extent as compared with the same modifications at C-2'; b) substitution of a methyl group for one of the 5'-CH2 protons does not lead to essential alterations of the substrate activity of such analogs vs. the natural substrates - uridine and ribofuranose-1-phosphate, respectively. PNP exhibits a very broad specificity for the purine acceptor.


Assuntos
Adenosina/análogos & derivados , Escherichia coli/enzimologia , Pentosiltransferases/metabolismo , Purina-Núcleosídeo Fosforilase/metabolismo , Uridina Fosforilase/metabolismo , Uridina/análogos & derivados , Especificidade por Substrato
8.
Antibiot Med Biotekhnol ; 31(3): 174-8, 1986 Mar.
Artigo em Russo | MEDLINE | ID: mdl-3521466

RESUMO

The conditions of synthesis of 9-beta-D-arabinofuranosyladenine, an antiviral nucleoside by intact cells of Escherichia coli capable of adenine transarabinosylation were studied. The cells were grown in meat-peptone broth supplemented with yeast extract. Cytosine arabinoside served as a donor of the arabinose residues. The pH value, temperature of the reaction medium and concentration of phosphate ions in it were shown to be significant factors defining the cell activity. Under optimal reaction conditions: 0.03 M potassium phosphate buffer, pH 6.75; 0.03 M cytosine arabinoside; 0.01 M adenine; 5 per cent of the cells; incubation time 12 hours; incubation temperature 60 degrees C the efficiency of 9-beta-D-arabinofuranosyladenine synthesis reached 90-95 mol % with respect to the initial adenine level.


Assuntos
Antivirais/metabolismo , Escherichia coli/enzimologia , Vidarabina/biossíntese , Adenina/metabolismo , Tampões (Química) , Meios de Cultura/metabolismo , Citarabina/metabolismo , Relação Dose-Resposta a Droga , Concentração de Íons de Hidrogênio , Temperatura Ambiente
9.
Antibiot Med Biotekhnol ; 30(8): 588-91, 1985 Aug.
Artigo em Russo | MEDLINE | ID: mdl-2998272

RESUMO

Strain 47/3 was isolated from the natural sources of Erwinia herbicola. The cells of this strain contain nucleoside phosphate transferase responsible for specific phosphorylation of the adenosine 5'-hydroxyl group. With the use of the strain intact cells, conditions for preparation of AMP were determined. The cells were grown in the meat-peptone broth supplemented with yeast extract. p-Nitrophenylphosphate was used as a donor of phosphate groups. It was shown that the concentration of the reaction substrates, their ratio and PH of the reaction mixture were factors defining the cell activity. Under the optimal conditions (0.2 M acetate buffer, pH 4.5; concentrations of p-nitrophenylphosphate and adenosine 96 and 12 mg/ml respectively; concentration of the cells 1 per cent) the cells phosphorylated adenosine with a yield of 74 mol %. This indicates that the method may be used for production of AMP in preparative amounts.


Assuntos
Monofosfato de Adenosina/biossíntese , Adenosina/metabolismo , Erwinia/enzimologia , Meios de Cultura/metabolismo , Relação Dose-Resposta a Droga , Concentração de Íons de Hidrogênio , Nitrofenóis/metabolismo , Compostos Organofosforados/metabolismo , Fosforilação , Fosfotransferases/metabolismo , Temperatura Ambiente
10.
Biokhimiia ; 44(10): 1819-25, 1979 Oct.
Artigo em Russo | MEDLINE | ID: mdl-508856

RESUMO

It was shown that La3+ ions are capable of precipitating the glucocorticoid receptor from rat liver. Treatment of cytosol containing either free receptor or the hormonereceptor complex with 0,005 M La(NO3)3 results in recptor precipitation. The pellet is readily dissolved in buffer with EDTA. Transcortin and transcortin-like proteins are not affected by La3+ ions. The lanthanium-treated receptor does not lose its ability to bind DNA and chromatin in vitro. It is suggested that precipitation by La3+ ions can be used for separation of the receptor from transcortin and transcortin-like proteins as well as for evaluation of binding parameters for steroid-receptor complexes in rat liver cytosol.


Assuntos
Fígado/metabolismo , Receptores de Glucocorticoides/isolamento & purificação , Receptores de Esteroides/isolamento & purificação , Animais , Citosol/metabolismo , Cinética , Lantânio , Ratos , Receptores de Glucocorticoides/metabolismo , Transcortina/isolamento & purificação
11.
Biokhimiia ; 43(7): 1184-9, 1978 Jul.
Artigo em Russo | MEDLINE | ID: mdl-698306

RESUMO

The binding of the receptor-glucocorticoid complexes from rat liver cells to DNA has been studied in an aqueous dextran-polyethylene glycol biphasic system. It has been shown that the capacity of DNA for binding hormone-receptor complexes is very large, and that no saturation is observed at physiological concentrations of the glucocorticoid receptor. The linear binding curve is indicative of low affinity of the DNA acceptor sites for the complexes. Cell cytosol contains substances which inhibit the binding of the receptor-dexamethasone complexes to homologous DNA.


Assuntos
DNA/metabolismo , Receptores de Glucocorticoides/metabolismo , Receptores de Esteroides/metabolismo , Animais , Citosol/metabolismo , Dextranos , Fígado/metabolismo , Polietilenoglicóis , Ratos
12.
Biofizika ; 20(4): 638-41, 1975.
Artigo em Russo | MEDLINE | ID: mdl-1201297

RESUMO

As a result of kinetic studies on acetylcholinesterase inhibition by allosteric effector d-tubocurarine it was shown that interaction between modifier and catalytic sites of rabbit and guinea pig acetylcholinesterase are different for these two species. Judging by the inhibition curves and sensitivity of d-tubocurarine theses differences involve enzyme microenvironment in the membrane. Addition to 7,15-10-6 M d-tubocurarune to solubilized preparation led to a significant fall in the value of Hill coefficient for enzyme-substrate interaction. This may be indicative of the changes in the conformational state of the enzyme after its dissociation from the membrane, i. e. of the membrane structure role in the formation of the structural and functional enzyme properties.


Assuntos
Acetilcolinesterase/metabolismo , Encéfalo/enzimologia , Cobaias/metabolismo , Coelhos/metabolismo , Animais , Inibidores da Colinesterase , Relação Dose-Resposta a Droga , Membranas/enzimologia , Ligação Proteica , Tubocurarina/farmacologia
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