Wyniki wyszukiwania

1

Purification and some properties of a novel dsRNA degrading nuclease bound to rye germ ribosomes

100%

Siwecka M. A.

Acta Biochimica Polonica

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1997

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tom 44

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nr 1

A two-step procedure including affinity chromatography for purification of rye germ ribosomal nuclease that degrades double-stranded RNA from a virus of Penicillium chrysogenum and the poly(I).poIy(C) complex was developed. The specific activity towards poly(I).poly(C) of the obtained nuclease preparations was 30 times as high as that of ribosomes. The recovery of activity was 3.4% when the Octyl-Sepharose column was used, and 2.0% in the case of the Phenyl-Sepharose column. On polyacrylamide/SDS gel electrophoresis the nuclease was resolved into two proteins of molecular mass 62 kDa and 57 kDa, respectively. 2-Mercaptoethanol and Mn2+ stimulated the activity of the purified enzyme. Glycerol (20%-50% concentration) stabilized enzyme. In addition to activity towards dsRNA and ssRNA the enzyme cleaves native and denatured DNA. It is suggested that this type of a nuclease takes part in regulation of the mRNA level in cytoplasm.

2

Rybozymy - perspektywy i ostatnie osiagniecia w badaniach i zastosowaniach

63%

Siwecka M. A.

Biotechnologia

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1992

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nr 3

74-76

3

The presence of deoxyribonucleolytic activity in cytoplasmic ribosomes of rye (Secale cereale L) germs

51%

Siwecka M. A., Rytel M., Szarkowski J. W.

Acta Biochimica Polonica

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1979

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tom 26

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nr 1-2

4

Nowe inhibitory cyklu rozwojowego wirusow rodziny Flaviviridae.

51%

Bretner M., Felczak K., Siwecka M. A., Kulikowski T.

Działalność Naukowa PAN. Wybrane Zagadnienia

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2002

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tom 14

50-52

5

Purification and characterization of nuclease I associated with rye germ ribosomes

51%

Siwecka M. A., Rytel M., Szarkowski J. W.

Acta Biochimica Polonica

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1989

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tom 36

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nr 1

6

Podstawowe procesy biochemiczne podczas kiełkowania nasion

51%

Golaszewski T., Siwecka M. A., Szarkowski J. W.

Postępy Biochemii

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1972

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tom 18

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nr 1

7

Synthesis and anti-HIV properties of novel 6-phenylselenenyl-5-propyluracils

39%

Miazga A., Felczak K., Siwecka M. A., Lipniacki A., Piasek A., Kulikowski T.

Acta Biochimica Polonica

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2007

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tom 54

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nr 4

863-868

Novel 6-phenylselenenyl-5-propyluracils were synthesized from 5-propyluracil with the use of regioselective synthesis to give 1-[(2-hydroxyethoxy)-methyl]-6-phenylselenenyl-5-propyluracil (6), 1-ethoxymethyl-6-phenylselenenyl-5-propyluracil (9) and 1-benzyloxymethyl-6-phenylselenenyl-5-propyluracil (10). Interaction of these compounds with recombinant HIV-1 reverse transcriptase (RT) was evaluated using a non-isotopic colorimetric method. Compounds 9 and 10 exerted potent HIV RT inhibition (IC500.06 and 0.05 μM respectively) while compound 6 showed moderate inhibition (IC50=3.5 μM). Potent anti-HIV-1 activity in MT-2 cells inoculated by a syncythia-in-ducing HIV-1 (cat #3 strain) laboratory isolate was exerted by compounds 9 and 10 (EC500.62 μM and 0.025 μM, respectively), while compound 6 showed only moderate activity (IC50=4.1 μM). In addition, compound 10 showed very good in vitro therapeutic index (TI > 2046), indicating that it is a potential anti-HIV/AIDS drug.

8

NTPase-helicase of Flaviviridae: inhibitors and inhibition of the enzyme

39%

Borowski P., Niebuhr A., Schmitz H., Hosmane R. S., Bretner M., Siwecka M. A., Kulikowski T.

Acta Biochimica Polonica

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2002

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tom 49

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nr 3

RNA nucleoside triphosphatases (NTPase)/helicases represent a large family of proteins that are ubiquitously distributed over a wide range of organisms. The enzymes play essential role in cell development and differentiation, and some of them are involved in transcription and replication of viral single-stranded RNA genomes. The enzymatic activities of a NTPase/helicase were also detected in the carboxyl-terminal non-structural protein 3 (NS3) of members of the Flaviviridae family. The crucial role of the enzyme for the virus life cycle was demonstrated in knock out experiments and by using NTPase/helicase specific inhibitors. This makes the enzyme an attractive target for development of Flaviviridae-specific antiviral therapies. This review will sum-marize our knowledge about the function and structure of the enzyme, update the spectrum of inhibitors of the enzymatic activities of the NTPase/helicase and describe the different mechanisms by which the compounds act. Some of the compounds reviewed herein could show potential utility as antiviral agents against Flaviviridae viruses.

9

Inhibition of the helicase activity of HCV NTPase-helicase by 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide-5'-triphosphate [ribavirin-TP]

33%

Borowski P., Lang M., Niebuhr A., Haag A., Schmitz H., Schulze zur Wiesch J., Choe J., Siwecka M. A., Kulikowski T.

Acta Biochimica Polonica

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2001

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tom 48

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nr 3

In the presented study the ribavirin-TP — an established inhibitor of the NTPase activity of the superfamily NTPase/helicases II — was investigated as an inhibitor of the unwinding activity of the hepatitis C virus (HCV) NTPase/helicase. The kinetics of the reaction revealed that ribavirin-TP reduces the turnover number of the helicase reaction by a mechanism that does not correspond to that of the inhibition of the NTPase activity. Our results suggest that derivatives of ribavirin-TP with enhanced stability towards hydrolytic attack may be effective inhibitors of the enzyme.

10

ATP-binding domain of NTPase-helicase as a target for hepatitis C antiviral therapy

33%

Borowski P., Mueller O., Niebuhr A., Kalitzky M., Hwang L. H., Schmitz H., Siwecka M. A., Kulikowski T.

Acta Biochimica Polonica

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2000

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tom 47

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nr 1

To enhance the inhibitory potential of 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (ribavirin) vs hepatitis C virus (HCV) NTPase/helicase, ribavirin-5'-triphosphate (ribavirin-TP) was synthesized and investigated. Ribavirin-TP was prepared with the use of modified Yoshikawa-Ludwig-Mishra-Broom procedure (cf. Mishra & Broom, 1991, J. Chem. Soc., Chem. Commun, 1276-1277) involving phosphorylation of unprotected nucleoside. Kinetic analysis revealed enhanced inhibitory potential of ribavirin-TP (IC50=40 µM) as compared to ribavirin (IC50 > 500 µM). Analysis of the inhibition type by means of graphical methods showed a competitive type of inhibition with respect to ATP. In view of the relatively low specificity towards nucleoside-5'-triphosphates (NTP) of the viral NTPase/helicases, it could not be ruled out that the investigated enzyme hydrolyzed the ribavirin-TP to less potent products. Investigations on non- hydrolysable analogs of ribavirin-TP or ribavirin-5'-diphosphate (ribavirin-DP) are currently under way.

Ograniczanie wyników

Purification and some properties of a novel dsRNA degrading nuclease bound to rye germ ribosomes

Rybozymy - perspektywy i ostatnie osiagniecia w badaniach i zastosowaniach

The presence of deoxyribonucleolytic activity in cytoplasmic ribosomes of rye (Secale cereale L) germs

Nowe inhibitory cyklu rozwojowego wirusow rodziny Flaviviridae.

Purification and characterization of nuclease I associated with rye germ ribosomes

Podstawowe procesy biochemiczne podczas kiełkowania nasion

Synthesis and anti-HIV properties of novel 6-phenylselenenyl-5-propyluracils

NTPase-helicase of Flaviviridae: inhibitors and inhibition of the enzyme

Inhibition of the helicase activity of HCV NTPase-helicase by 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide-5'-triphosphate [ribavirin-TP]

ATP-binding domain of NTPase-helicase as a target for hepatitis C antiviral therapy