Helicases convert double-strand DNA into single-strand DNA, a DNA unwinding process energized by ATP hydrolysis. DNA helicases are essential during DNA replication, repair, recombination and transcription. The Helicase DNA Unwinding Assay is based on measurement of the DNA unwinding activity using a fluorescence-labelled duplex DNA substrate. The fluorescence group Quazar 570 is linked to one strand of DNA and its fluorescence is quenched by the dye BHQ-2 that is linked to the other strand of DNA. Once the duplex DNA is separated by the helicase coupled with ATP hydrolysis, the single-strand DNA product is trapped by a trapping DNA and the fluorescence is regenerated.  It is a continuous assay. The DNA helicase assays can be performed in a 96-well plate or 384-well plate format for high throughput screening of DNA helicase inhibitors. 

Helicases also have DNA-stimulated ATPase activity. The Helicase ATPase Assay is based on detection of the phosphate produced by the ATP hydrolysis reaction in the presence of a single-strand DNA. 

The Helicase DNA Unwinding Assay Kit (Catalog No.  DU050K) includes 300 µl of 10 x assay buffer, 25 µl of 100 x  DNA duplex, 125 µl of 100 x trapping DNA and 25 µl  of 100 x ATP.   The kit is for 50 assays of DNA helicase assays in a 384-well assay format or 25 assay in a 96-well plate format.  The kit does not include the helicase.   

Human Bloom’s syndrome (BLM) Helicase Assays

The Human BLM Helicase DNA Unwinding Assay Kit Plus (Catalog No.  DU050BLM) includes 300 µl of 10 x assay buffer, 25 µl of 100 x  DNA duplex, 125 µl of 100 x trapping DNA, 100 ul of 100 x human BLM helicase and 25 µl  of 100 x ATP.   The kit is for 50 assays of DNA helicase assays in a 384-well assay format or 25 assay in a 96-well plate format.   

The Human BLM Helicase ATPase assay Kit Plus (Catalog No.  BLM100ATP) includes 400 ul of 10 x assay buffer, 30 µl of 100 x DNA, 30 µl of 100 x BLM helicase, 30 µl of 100 x ATP and 5 ml of dye for 100 assays in a 384-well assay format or 50 assays in 96-well assay format.

Human DNA Polymerase Theta Assays

The Human DNA Polymerase Theta Helicase Assay Kit Plus (Catalog No.  DU050PQ) includes 300 µl of 10 x assay buffer, 25 µl of 100 x  DNA duplex, 125 µl of 100 x trapping DNA, 25 µl of 100 x human DNA polymerase theta N-terminal domain and 25 µl  of 100 x ATP.   The kit is for 50 assays of DNA helicase assays in a 384-well assay format or 25 assay in a 96-well plate format. 

The Human DNA Polymerase Theta ATPase Assay Kit Plus (Catalog No.  HDPQ100KE) includes all the assay kit components for 100 assays in a 384-well plate assay format: 400 µl of 10 x Buffer, 33 µl of 100 x DNA (20 µM), 33 µl of 100 x ATP (25 mM), 33 µl of 100 x human DNA polymerase theta N-terminal domain and 5 ml of MPA3000 dye.