Human DNA topoisomerase I (Topo I) is a validated anticancer drug target. Compounds inhibiting Topo I have elevated levels of topo I and shown activities against human cancer. In the cells, Topo I relaxes the supercoiled DNA by transiently cleaving and rejoining one strand of the DNA duplex. The in vitro DNA relaxation react ion catalyzed by human Topo I can be used for screening of inhibitors in drug discovery. ProFoldin offers high quality human DNA topoisomerase I enzyme and its assay reagents for high throughput assays  in a 96-well plate format. ProFoldin also offers the gel-based assay for human DNA topoisomerase I.

One unit of human topoisomerase I is the amount of enzyme that relaxes 0.25 μg of supercoiled plasmid DNA in 30 minutes at 37 °C.

Human Topoisomerase I, 10,000 Units (Catalog No. HTOPI-010) contains 20 µl of 500 U/µl of purified human Topoisomerase I form sf9 cells and 1 ml of 10 x assay buffer.

Human Topoisomerase I, 40,000 Units (Catalog No. HTOPI-040) contains 20 µl of 2,000 U/µl of purified human Topoisomerase I form sf9 cells and 4 ml of 10 x assay buffer.

Human Topoisomerase I, 100,000 Units (Catalog No. HTOPI-100) contains 50 µl of 2,000 U/µl of purified human Topoisomerase I form sf9 cells and 10 ml of 10 x assay buffer.

For high throughput assay kits of human Topo I, please click here.