The DNA Topoisomerase IV Assay Kit is based the principle that the decatenated DNA is separated from the concatenated DNA by a quick and easy spin-column process.  The concatenated DNA stays on the column, while the decatenated DNA is eluted.  The eluted DNA is quantified by fluorescence.   Each kit includes the assay buffer (T4 buffer), concatenated DNA, spin columns and loading solution for 20 assays of DNA decatenation reactions. The assay buffer is optimized for bacterial topoisomerase IV.