20(S)camptothecin has shown promising activity against a range of tumour types. This CPT derivative causes cell toxicity by stabilizing a ternary complex between the nuclear enzyme topoisomerase I (topo I) and double-stranded DNA, leading to single and double strand breaks. TopoGEN provides this reagent as a control poison/inhibitor of topoisomerase I. For in vitro cleavage detection, we recommend that the drug be tested over a wide range of uM concentrations; however, cleavages are strongly influenced by the amount of topoisomerase in the reaction as well as the type of assay being employed (SDSK+ vs. Radioac- tive End Labeled DNA vs. testing for plasmid cleavages). Note that large amounts of enzyme will be required to detect cleavage complex, compared to assays that measure catalytic activity.
Molecular Formula: C20H19N3O6
Molecular Weight: 393.35