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

Human lymphocytes lose viability when incubated in vitro with either aphidicolin, an inhibitor of DNA polymerase alpha, or with the combination of aphidicolin and deoxycoformycin (an adenosine deaminase inhibitor). Loss of viability was assayed by vital staining with fluorescein diacetate as well as examination of Wright stained preparations and the appearance of cellular debris observed using an electronic cell counter. The loss of viability was rapid with the combination of aphidicolin (2 micrograms/ml) and deoxycoformycin (1 microgram/ml) with essentially complete loss of viability after 72 hours of incubation. This drug combination produces DNA single strand breaks after 24 and 48 hours of incubation at a level equivalent to that produced by 200 or 400R of X-irradiation, respectively.
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PMID:Aphidicolin and deoxycoformycin cause DNA breaks and cell death in unstimulated human lymphocytes. 642 3

Toxiusol, a natural product isolated from the Red Sea sponge Toxiclona toxius, has been shown to be a potent inhibitor of various viral reverse transcriptases (RT) [i.e., of human immunodeficiency virus (HIV-1), equine infectious anemia virus, and murine leukemia virus] and cellular DNA polymerases (i.e., of DNA polymerases alpha and beta and Escherichia coli DNA polymerase I). A thorough investigation of the mode of inhibition was conducted with HIV-1 RT-associated DNA polymerase activity. The inhibition is unaffected by the nature of template-primer used. The inhibitory active site of toxiusol is attributable to the polar moieties at the benzene ring. The presence of either sulfate groups in the natural lead compound or hydroxyl groups in the corresponding hydroquinone is critical, because both compounds are equally effective at low micromolar concentrations. Conversely, the presence of acetyl groups in the same position in the derivative toxiusol diacetate lowers significantly or abolishes the inhibitory activity. Toxiusol binds the HIV-1 RT irreversibly and in a noncompetitive way with high affinity (Ki = 1.2 microM), probably through polar groups. The replacement with acetyl moieties in the analog toxiusol diacetate hampers the binding of the inhibitor to the enzyme (Ki increases to about 26 microM). Still, the compound binds irreversibly, probably through its hydrophobic structure skeleton. Toxiusol diacetate loses its ability to inhibit the first step in the DNA polymerization process (that is, the formation of the DNA-enzyme complex as measured by a gel retardation assay), which contributes to its poor inhibitory capacity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Mechanism of inhibition of HIV reverse transcriptase by toxiusol, a novel general inhibitor of retroviral and cellular DNA polymerases. 753 6

A 5' nuclease assay has been developed to detect viable Listeria monocytogenes. The assay targets the hemolysin A (hlyA) transcript, which is found only in L. monocytogenes. The single-tube, reverse transcriptase (RT), fluorogenic probe-based assay was formatted by using Tth DNA polymerase whose activity was modulated by using the manganese-chelating morpholinepropanesulfonic acid (MOPS) buffer. This assay was quantitative over a 3-log-unit range of template concentrations when tested with an in vitro-transcribed hlyA mRNA. The viability of L. monocytogenes was reduced by heating at various temperatures and times up to a maximum of a 9-D inactivation. The location of the primer had a pronounced effect on the utility of the assay, and primers located in the most distal regions of the hlyA transcript appeared to correlate with the number of CFU while primers located more internal on the amplicon overestimated the cell viability. The assay with primers that included the 3' end of the transcript was an accurate indicator of viability as measured by CFU determination or staining with 5-sulfofluorescein diacetate.
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PMID:Detection of viable Listeria monocytogenes with a 5' nuclease PCR assay. 1022 10