ProFoldin offers various non-radioactive and high-throughput assays for all topoisomerase functions including DNA relaxation, DNA supercoiling, DNA decatenation, DNA cleavage (Topoisomerase poisons) and ATP hydrolysis. For more information please visit The Topo World. 

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.

For human DNA topoisomerase I and its DNA relaxation assays, please click here

For gel-based E.coli DNA topo I DNA relaxation assay, please visit here.