5001-1 In Vitro Screen for Topo I Catalytic Inhibitors

5001-2 In Vitro Screen for Topo II Catalytic Inhibitors

5001-3 In Vitro Screen for E. coli DNA Gyrase Catalytic Inhibitors

5001-4 In Vitro Screen for E. coli Topo IV Catalytic Inhibitors

5001-5 In Vitro Screen for S. aureus DNA Gyrase Catalytic Inhibitors

5001-6 In Vitro Screen for S. aureus Topo IV Catalytic Inhibitors

5002-1 In Vitro Screen for Topo I Poisons

5002-2 In Vitro Screen for Topo II Poisons

5002-3 In Vitro Screen for E. coli DNA Gyrase Poisons

5002-4 In Vitro Screen for E. coli Topo IV Poisons

5002-5 In Vitro Screen for S. aureus DNA Gyrase poisons

5002-6 In Vitro Screen for S. aureus Topo IV Poisons

We will test for catalytic inhibition for the selected topoisomerases above. These assays will determine whether a given compound is capable of blocking the catalytic action of topoisomerases. The assays will be designed to yield approximate IC50 values and thus will involve testing a range of drug concentrations. At a minimum two screening assays will be performed: one over a wide (multi-log) range of test compound X and one over a narrow range to more accurately zero-in on the IC50 value for compound X. For topo I assays, we will perform relaxation of a high affinity topo I target plasmid DNA (pHOT1). For topo II assays, we employ kDNA decatenation assays. Gel data will be quantified using the Gene Flash gel documentation system. A detailed report will be prepared and provided to the customer including JPG images and plots of inhibition. These reports are filed electronically as attachments emailed directly to the customer. There is a single upcharge for the first compound and subsequent compounds are heavily discounted. This service is designed primarily for those customers that wish to test whether a given compound inactivates the enzymatic action of topoisomerase I or II.

These are also called DNA cleavage assays. To test for a topo specific poison, reactions are carried out with a plasmid DNA target and relatively high levels of topo I or II. Reactions are performed in the presence of the test compound, and terminated with a protein denaturant such as SDS. For topo I, formation of nicked DNA is measured on gels and for topo II formation of linear DNA is quantified. Controls with known topo poisons are performed for comparison. The test drugs are titrated over a wide range to determine the efficiency of cleavage trapping relative to known poisons such as camptothecin (topo I) or etoposide (topo II). This comparison will determine whether a new compound works as well as known, clinically used, topo targeting agents. As with Level I assays, a detailed report will be prepared and provided to the customer including JPG images. These reports are filed electronically as attachments emailed directly to the customer. There is a single upcharge for the first compound and subsequent compounds are heavily discounted. 

Screens for poisons, inhibitors and topo agents.

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108 Aces Alley
Port Orange, Florida
32128
Tel. 614-451-5810
Fax 614-559-3932
Sales: info@topogen.com
Tech: support@topogen.com