The GTPase-Glo™ Assay measures GTPase activity by detecting the amount of GTP remaining after GTP hydrolysis in a GTPase reaction. After the GTPase reaction, addition of the GTPase-Glo™ Reagent converts any remaining GTP into ATP, which is converted to a luminescent signal upon addition of the Detection Reagent.
GTPase, GAP and GEF activity is inversely correlated to the amount of light produced. A highly active GTPase hydrolyzes more GTP, reducing the amount of ATP produced from GTP and reducing light output. A less active GTPase hydrolyzes less GTP, leaving a larger amount of GTP to be converted to ATP and producing more light.
The diagram on the left shows GTPase in active and inactive phases in relation to GDP and GTP. The diagram on the right is a schematic of the GTPase-Glo™ Assay protocol.