9H-(1,3-Dichloro-9,9-dimethylacridin-2-one-7-yl) phosphate, Bis(triethylammonium) salt
DDAO-phosphate is a long-wavelength, phosphatase substrate for both solution-based assays and the amplified detection of specific targets on blots. Hydrolysis of the phosphate bond yields a brightly red-fluorescent product with absorption/emission maxima of 646/659 nm that is efficiently excited by the 633 nm spectral line of the He-Ne laser. The shift of emission maxima between DDAO-phosphate and the dephosphorylated product is larger than 200 nm and permits both species to be easily distinguished. DDAO phosphate has good water solubility, a low KM and a high turnover rate.
