This product includes 480 ul of 10 x Buffer, 405 ul of 10 x supercoiled plasmid DNA, 45 ul of 100 x S. aureus topoisomerase IV, 405 ul of 10 mM ATP, 8 ul of 4500 x fluorescence dye H19 and 3 ml of 10 x H19 dilution buffer for 100 assays of DNA relaxation reactions in a 96-well assay format.