Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Revistin, a substance that strongly inhibits the reverse transcriptase activity of murine leukemia virus in our screening system, was obtained from a cultured broth of a soil streptomyces which was closely related to Streptomyces filipinensis. The assay method for the activity was based on the inhibition by a test material of the incorporation of 3H-dTMP into DNA synthesized by the reverse transcriptase of an oncogenic RNA virus. Crude revistin was isolated by serial procedures of salting out with ammonium sulfate and precipitation with cetylpyridinium chloride. The crude material showed neither antibacterial nor antifungal activity. It exhibited against splenomegaly in mice caused by Rauscher leukemia virus infection.
...
PMID:Revistin found by screening for inhibitors of reverse transcriptase of an oncogenic virus. 5 48

The addition of iododeoxyuridine to P3HR-I cell cultures led to a large increase in both Epstein-Barr virus (EBV)-induced DNA polymerase activity and early antigen-positive cells. This EBV-induced DNA polymerase was separated from the cellular alpha- and beta-polymerases by sequential column chromatography on Sepharose 6B, DEAE-cellulose, and phosphocellulose, resulting in partial purification of about 320-fold. The partially purified-EBV DNA polymerase could be distinguished from the cellular DNA polymerases by its activation by salts, its catalytic properties, and its degree of sensitivity to N-ethylmaleimide, phosphonoacetic acid, araATP, and araCTP. The viral polymerase showed properteis similar to those reported for other herpesvirus DNA polymerases. The enzyme exhibited optimal activity for copying activated calf DNA in the presence of 50 mH (NH4)2SO4 and was resistant to 150 mM (NH4)2SO4. It utilized with high efficiency template-primer poly(dC)-oligo(dG)12-18 or poly(dA)-oligo(dT)12-18, but failed to copy poly(rA)-oligo(dT)10 and oligo(dT)10, indicating that this enzyme has characters distinct from DNA polymerase gamma, reverse transcriptase, and terminal deoxynucleotidyl transferase. Phosphonacetic acid inhibited not only EBV DNA polymerase, but also, to a lesser degree, the cellular polymerase alpha. AraATP did not severely inhibit viral activity, whereas the polymerase alpha was inhibited most effectively. Both EBV polymerase and polymerase alpha were inhibited at a comparable level by araCTP.
...
PMID:Characterization of an Epstein-Barr virus-induced DNA polymerase. 21 9

The pol I gene from HIV-1 encoding the protease, reverse transcriptase (RT) and endonuclease has been expressed in Escherichia coli. By modifying the fermentation conditions and developing a new purification scheme, the yield of purified RT has been increased substantially compared with that obtained in an earlier procedure. The expressed RT was purified to homogeneity by ammonium sulphate fractionation followed by chromatography on DEAE Sepharose, Heparin Sepharose, S Sepharose and Poly(A)-Sepharose. The purified HIV-RT is a heterodimer (p66/p51) with an isoelectric point close to 8 and with a tendency to aggregate. The proteolytic product (p51), corresponding to the N-terminal end of the RT molecule, was isolated and identified, as were also some bacterial polypeptides that co-elute with HIV-RT during the early stages of the purification. The heterodimer was crystallized in several morphological forms using the vapour-diffusion hanging drop technique. To concentrate the protein and to change the buffer for crystallization, reverse-salt-gradient chromatography and micropreparative columns were used. The best crystals diffracted to 9 A resolution. The best crystals of native RT diffracted to 9 A resolution and in complex with nucleic acids to 4.5 A resolution (using a rotating anode X-ray source).
...
PMID:Purification, characterization and crystallization of recombinant HIV-1 reverse transcriptase. 137 51

In a search for compounds active against human immunodeficiency virus type 1 (HIV-1), it was found that the novel low-molecular weight immunoenhancer ammonium trichloro(dioxyethylene-O,O'-) tellurate (AS101) suppresses production of HIV-1 in vitro. Treatment of HIV-1-infected peripheral blood mononuclear cells (PBMC) with increasing concentrations of AS101 resulted in substantial inhibition of virus production as measured by both reverse transcriptase (RT) activity and antigen presence in supernatants of treated cells. AS101 had no effect on PBMC viability, growth, or morphology up to a concentration of 15 microM for 14 days. To elucidate a possible mechanism for the inhibition of AS101, we have analyzed the effect of the drug on the catalytic functions associated with HIV RT, namely the RDDP, DDDP, and RNase H activities. RDDP and DDDP activities were impaired by the drug with calculated IC50 value of about 4 microM. On the other hand, the RNase H activity was less sensitive to AS101, with an apparent IC50 value of about 30 microM. The anti-HIV-1 activity of AS101 as reflected by inhibition of the different catalytic functions associated with viral RT, in the absence of drug-related toxicity to lymphocytes, together with its immunomodulating activity strongly argues in favor of its evaluation, as a therapeutic agent for patients with HIV infection.
...
PMID:Inhibition of the reverse transcriptase activity and replication of human immunodeficiency virus type 1 by AS 101 in vitro. 138 Dec 5

Human immunodeficiency virus-1 reverse transcriptase-p66 is surprisingly unstable at 4 degrees C in a typical reverse transcriptase buffer that provides complete stability when enzyme is frozen at -70 degrees C. Incorporation of (rA)n(dT)12-18 template-primer in the buffer vastly improved solution stability of dilute enzyme. Incorporation of 1.0 M ammonium phosphate in the buffer promoted an unexpected and reproducible approximately 260% activation of enzyme. In addition, even enzyme that had been inactivated to 13% of its initial activity could be reactivated to the same approximately 260% higher activity level indicating a reversible interconversion of two forms of the enzyme. The effects of chaotropic and antichaotropic salts coupled with a prior observation of p66 monomer-dimer equilibrium provide suggestive evidence that these two forms of enzyme are monomeric and dimeric p66.
...
PMID:Stabilization and activation of recombinant human immunodeficiency virus-1 reverse transcriptase-P66. 169 Sep 91

Simian immunodeficiency virus protease (SIV-PR) was produced in Escherichia coli with a recombinant expression system in which the mature enzyme autoprocessed from a precursor form. Recombinant SIV and HIV-1 (human immunodeficiency virus, type 1) proteases were purified from bacterial cell lysates by use of sequential steps of ammonium sulfate precipitation and size-exclusion and ion-exchange chromatography. The amino acid composition, amino-terminal sequence, and molecular weight (monomer) of the recombinant SIV-PR were in accord with that of the 99 amino acid polypeptide predicted from the SIVMac-PR nucleotide sequence. The active form of SIV-PR was shown to be dimeric by gel filtration chromatography. Inhibition by pepstatin A, time-dependent inactivation by 1,2-epoxy-3-(4-nitrophenoxy)propane, and pH rate profiles using oligopeptide substrates demonstrated that SIV-PR behaves as an aspartic protease. Recombinant HIV-1 Pr55gag precursor was processed in vitro by SIV-PR and HIV-1 PR with indistinguishable proteolytic patterns upon NaDodSO4-polyacrylamide gel electrophoresis. Oligopeptide substrates for HIV-1 PR were found to be suitable substrates for recombinant SIV-PR with the exception of a peptide containing the site identified for p66/p51 cleavage (Phe*Tyr) within HIV-1 reverse transcriptase (RT). Several synthetic peptide analogue inhibitors of HIV-1 PR were also potent inhibitors of SIV-PR, indicating that SIV infection in macaques and rhesus monkeys should be useful models for the preclinical evaluation of acquired immunodeficiency syndrome (AIDS) therapeutics targeted towards the virally encoded HIV-1 protease.
...
PMID:Purification and biochemical characterization of recombinant simian immunodeficiency virus protease and comparison to human immunodeficiency virus type 1 protease. 188 29

A series of synthetic lipids containing a two- or three-carbon backbone substituted with a thio, oxy, or amidoalkyl functionality and either a phosphocholine or quaternary ammonium moiety was evaluated as potential anti-HIV-1 agents. Several analogues were identified as possessing activity with the most promising compound being rac-3-octadecanamido-2-ethoxypropylphosphocholine (8). Compound 8 exhibited an IC50 for the inhibition of plaque formation of 0.16 microM which was 84-fold lower than the IC50 value determined for CEM-SS cell growth inhibition. Initial mechanistic studies have indicated that these compounds, unlike AZT, are not reverse transcriptase (RT) inhibitors, but instead appear to inhibit a late step in HIV replication involving virus assembly and infectious virus production. Since these lipids are acting via a different mechanism, they represent an alternative approach to the chemotherapeutic treatment of AIDS as well as candidates for combination therapy with AZT.
...
PMID:In vitro evaluation of phosphocholine and quaternary ammonium containing lipids as novel anti-HIV agents. 201 13

The water-soluble ammonium salt of 3'-azido-5'-(O-ethoxycarbonylphosphinyl)-3'-deoxythymidine (ECP-AZT), the prototype of a novel class of compounds incorporating two active antiretroviral agents, in this case 3'-azido-3'-deoxythymidine (AZT) and phosphonoformic acid (PFA), within the same structure, was synthesized and tested as an inhibitor of the replication of human immunodeficiency virus type 1 (HIV-1) in Jurkat cells, a CD4+ human T-lymphocyte cell line. The corresponding 5'-(O-methoxycarbonylphosphinyl) derivative (MCP-AZT) was also prepared. The rationale for the synthesis of ECP-AZT and MCP-AZT was that they may be cleaved intracellularly to AZT and PFA via hydrolysis of the phosphate ester bond or to AZT 5'-monophosphate by oxidative cleavage of the carbon-phosphorus bond. ECP-AZT was found to block viral replication at a 50% inhibitory concentration (IC50) of ca. 10(-6) M as measured by reverse transcriptase (RT) activity in supernatants from cultures of infected cells. Little or no inhibition of cell growth was observed at this concentration, and there was less than 20% inhibition of cell growth at 10(-4) M. AZT itself was a more potent inhibitor of HIV-1 replication than ECP-AZT, but was also more cytotoxic. The antiviral selectivity of ECP-AZT, defined as the ratio IC50 (virus inhibition)/IC50(cell growth inhibition), was in the range considered to be therapeutic for anti-AIDS nucleosides.
...
PMID:Inhibition of human immunodeficiency virus type 1 replication by phosphonoformate esters of 3'-azido-3'-deoxythymidine. 222 76

A Keggin polyoxotungstate PM-19 K7[PTi2W10O40].6H2O was found to be a potent inhibitor of the replication of human immunodeficiency virus (HIV), which causes acquired immunodeficiency syndrome (AIDS), in OKT4+ cells. In contrast, the effect of HPA 23 (NH4)17Na[NaSb9W21O86], an inhibitor of reverse transcriptase of HIV, was not significant.
...
PMID:Inhibition of replication of human immunodeficiency virus by a heteropolyoxotungstate (PM-19). 233 49

Antiviral agents under investigation for the treatment of patients infected with the human immunodeficiency virus (HIV) are reviewed. Multiple mechanisms exist by which antiviral agents might inhibit the replication of HIV or eradicate its latent form in affected cells, or both. These mechanisms include (1) interference with the cell surface receptor for HIV, (2) prevention of uncoating of viral particles, (3) inhibition of reverse transcriptase, (4) prevention of integration and posttranscription processing, (5) interference with viral assembly, and (6) interference with virus release. Most agents developed thus far work by inhibiting HIV reverse transcriptase. Suramin, ribavirin, ammonium 21-tungsten-9-antimoniate (HPA-23), foscarnet (phosphonoformate, PFA), inosine pranobex (isoprinosine), peptide T, ampligen, AL 721, dideoxycytidine, and zidovudine (formerly azidothymidine) have antiretroviral activity in vitro. To date zidovudine is the only antiretroviral agent approved by the FDA as clinically effective. However, zidovudine has serious toxicities, including neutropenia and anemia; in some patients dosage reduction or cessation of therapy may be necessary. Because treatment with zidovudine does not cure HIV infection, numerous studies are under way with other anti-HIV agents. Ultimately, combinations of agents probably will be used to suppress or eradicate HIV. While the search for more efficacious and less toxic treatments continues, the development of zidovudine in such a short time provides hope that progress toward a cure will be made rapidly.
...
PMID:Development of antiviral agents for the treatment of human immunodeficiency virus infection. 332 38


1 2 3 4 5 6 7 8 Next >>

---