Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An aqueous extract of Phyllanthus niruri (Euphorbiaceae) inhibited human immunodeficiency virus type-1 reverse transcriptase (HIV-1-RT). The inhibitor against HIV-1-RT in this plant was purified by combination of three column chromatographies, Sephadex LH-20, cellulose, and reverse-phase high-performance liquid chromatography. The inhibitor was then identified by nuclear magnetic resonance (NMR) spectra as repandusinic acid A monosodium salt (RA) which was originally isolated from Mallotus repandus. The 50% inhibitory doses (ID50) of RA on HIV-1-RT and DNA polymerase alpha (from HeLa cells) were 0.05 microM and 0.6 microM, respectively, representing approximately a 10-fold more sensitivity of HIV-1-RT compared with DNA polymerase alpha. RA was shown to be a competitive inhibitor with respect to the template-primer while it was a noncompetitive inhibitor with respect to the substrate. RA as low as 10.1 microM inhibited HIV-1-induced cytopathogenicity in MT-4 cells. In addition, 4.5 microM of RA inhibited HIV-1-induced giant cell formation of SUP-T1 approximately 50%. RA (2.5 microM) inhibited up to 90% of HIV-1 specific p24 antigen production in a Clone H9 cell system.
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PMID:HIV-1 reverse transcriptase inhibitor from Phyllanthus niruri. 128 10

Azodicarbonamide tested as an anti-HIV agent was reported to expulse zinc from viral zinc-cysteine factors and to inhibit calcium mobilization machinery. It has structural analogy with hydroxyurea that inhibits ribonucleotide reductase and could also act on this target. Azodicarbonamide was therefore tested for its capacity to modulate deoxyribonucleotides triphosphate pools alone or in combination with other agents in the lymphoblastic SUP-T1 cell line susceptible to HIV infection. The deoxyribonucleotides triphosphate were evaluated by an enzymatic assay using sequenase. Two hours exposure of SUP-T1 cells to 100 microM azodicarbonamide induced a 50% reduction of each deoxyribonucleotide triphosphate. Among other inhibitors of nucleotide metabolism (hydroxyurea, methotrexate and thymidine), hydroxyurea only reproduces the effect of azodicarbonamide. This suggests, but does not demonstrate directly, that azodicarbonamide inhibits ribonucleotide reductase activity. The combination of azodicarbonamide with each of these inhibitors affected particularly the dCTP pool. During this study it was also suggested that azodicarbonamide could interfere with thymidine phosphorylation. Thymidine phosphorylating activity was measured with 3H-thymidine as substrate. In acellular preparations, azodicarbonamide also non-competitively inhibits thymidine phosphorylating activity. This effect was not reproduced by hydroxyurea. Thus, in vitro azodicarbonamide decreases the intracellular pool of deoxyribonucleotide and thymidine phosphorylation.
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PMID:Ribonucleotide reductase and thymidine phosphorylation: two potential targets of azodicarbonamide. 1214 96