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Topoisomerases and Enzymatic Activity: A How-To Guide to Establishing Activity

Topoisomerases and Enzymatic Activity: A How-To Guide to Establishing Activity

If you experience low or no activity with our enzymes, consider doing a ‘reconstruction’ type of experiment as follows. Note that this is generally good practice upon receipt of new enzyme from TopoGEN, just to verify that everything is working properly in your lab. FIRST, When you receive your product, be sure to store as directed by the product literature. Often this means placing immediately at -70ºC. In some cases you can thaw and aliquot the enzyme (not less than…

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Topo I Assay Quickstart: How to get the assay properly validated and established in my lab?

Topo I Assay Quickstart: How to get the assay properly validated and established in my lab?

Whether you are conducting your first topo I specific assay or you have multiple publications identifying novel topoisomerase inhibitors, you are aware that working with catalytically active proteins can involve extra time constraints if you do not first validate the working conditions of your assay. The following simple experiment should be performed when you receive your human topoisomerase I enzyme and topoisomerase I assay kit. You must show that in your lab, you can detect topo activity. This experiment is…

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Topoisomerase II Drug Screening and Xanthocidin

Topoisomerase II Drug Screening and Xanthocidin

These researchers have cleverly identified a way to synthesize derivatives of an unstable compound group with potential as Topoisomerase IIa inhibitors. Topo II and Drug Screening kits for the analysis of enzyme reactivity and DNA cleavage were provided by TopoGEN. Article Source: The Pharmaceutical Society of Japan Biological and Pharmaceutical Bulletin Xanthocidin Derivatives as Topoisomerase IIα Enzymatic Inhibitors Abstract Few studies have examined xanthocidin, a biotic isolated from Streptomyces xanthocidicus in 1966, because its supply is limited. Based on its…

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Study Reveals Novel Approach to Reducing Toxic Effects of Amonafide

Study Reveals Novel Approach to Reducing Toxic Effects of Amonafide

This study which originally was published in Bioorganic and Medicinal Chemistry in November 2013, describes a novel approach to reducing the toxic side effects of amonafide, a drug used in the treatment of cancer which is considered a topoisomerase II poison. Article Source: Science Direct Synthesis and study of antiproliferative, antitopoisomerase II, DNA-intercalating and DNA-damaging activities of arylnaphthalimides Abstract A series of arylnaphthalimides were designed and synthesized to overcome the dose-limiting cytotoxicity of N-acetylated metabolites arising from amonafide, the prototypical…

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Topo I and Cobalt Complex

Topo I and Cobalt Complex

Revealing new paper on metallo-inhibitors. Article Source: Science Direct Synthesis and structure elucidation of a cobalt(II) complex as topoisomerase I inhibitor: In vitro DNA binding, nuclease and RBC hemolysis Abstract Metal-based cancer chemotherapeutic agent of the type Co(II) complex [Co(mpca)2]·H2O (1), where, Hmpca = 9-methyl-[1,10]phenanthroline-2-carboxylic acid was synthesized and characterized by various spectroscopic and analytical techniques and further authenticated by single crystal X-ray diffraction methods. In vitro DNA binding studies of complex 1 with CT DNA was carried out by…

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Supercoiling DNA with Reverse Gyrase

Supercoiling DNA with Reverse Gyrase

A new reverse gyrase from Pyrobaculum species has been identified with some novel properties. It combines helicase with topoisomerase domains. Very interesting from an evolutionary perspective. Article Source: The Journal of Biological Chemistry The reverse gyrase form Pyrobaculum calidifontis, a novel extremely thermophilic DNA topoisomerase endowed with DNA unwinding and annealing activities Abstract Reverse gyrase is a DNA topoisomerase specific of hyperthermophilic bacteria and archaea. It catalyses the peculiar ATP-dependent DNA positive supercoiling reaction and might be involved in the…

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Topoisomerase II Targeting and Resveratrol

Topoisomerase II Targeting and Resveratrol

In this paper the authors use a decatenation assay to identify some new topoisomerase II inhibitors from resveratrol. kDNA substrate was provided by TopoGEN. Article Source: Journal of Agricultural and Food Chemistry Topoisomerase II-Targeting Properties of a Grapevine-Shoot Extract and Resveratrol Oligomers Abstract Grapevine-shoot extracts (GSE), containing trans-resveratrol and resveratrol oligomers, are commercially available as food supplements. Considering the topoisomerase-targeting properties of trans-resveratrol, the question of whether GSE affect these enzymes, thereby potentially causing DNA damage, was addressed. In a…

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Topoisomerase Inhibition and Torsional Stress

Topoisomerase Inhibition and Torsional Stress

Topology is critical in allowing chromatin to function in a normal manner. DNA templating is clearly impacted when enzymes that relieve strain are blocked in a chromatin context. Specifically, inhibition of topoisomerases leads to rapid accumulation of torsional strain accompanied by changes in Pol II kinetics and destabilization of nucleosomes. Transcription-generated torsional stress destabilizes nucleosomes Article Source: Nature Abstract As RNA polymerase II (Pol II) transcribes a gene, it encounters an array of well-ordered nucleosomes. How it traverses through this…

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