Topoisomerase DNA relaxation assays
DNA relaxation is an essential process during DNA replication. The primary function of topoisomerase I is
DNA relaxation in both bacteria and mammalian cells. Bacterial topoisomerase IV and human topoisomerase
II also have DNA relaxation activities. The Topoisomerase DNA relaxation Assay Kit is based on the
principle that the supercoiled DNA and relaxed DNA yield different fluorescent intensity when interact with
fluorescence dye H19. The relaxed DNA suppresses the fluorescent intensity much more than the
supercoiled DNA. Therefore, when the supercoiled DNA is converted into its relaxed form, the fluorescent
signal decreases. The change of fluorescence intensity is used to measure the relaxation reaction.
Bacterial topoisomerase_DNA relaxation assay kits
E. coli DNA Topoisomerase I Assay Kit Plus
Includes 160 µl of 10 x Buffer T1, 84 µl of 10 x supercoiled plasmid DNA, 10 µl of 100 x E. coli topoisomerase
I, 8 µl of 1500 x Dye H19 and 500 µl of 10 x H19 dilution buffer. It is for 20 DNA relaxation assays in a 96-well
plate format or 40 assays in a 384-well assay format.
E. coli DNA Topoisomerase I Assay Kit Plus-100
Includes 480 µl of 10 x Buffer T1, 405 µl of 10 x supercoiled plasmid DNA, 40 µl of 100 x E.coli topoisomerase I
enzyme, 20 µl of 1500 x Dye H19 and 3000 µl of 10 x H19 dilution buffer. It includes all the reagents for 100
DNA relaxation assays in a 96-well plate format or 200 assays in a 384-well assay format.
DNA Topoisomerase I Assay Reagent Set for HTS
The Reagent Set is designed for drug discovery HTS uses. Each reagent set includes the reaction buffer and
fluorescence dye H19 for 1000 assays of DNA relaxation reactions in a 96-well plate assay format or 2000
assays in a 384-well assay format. E. coli topoisomerase I (TOP1-100EC) and supercoiled DNA are not
included in the set. Supercoiled plasmid PBR322 from any commercial source can be used.