Alkaline phosphatase
The specificity of ZFPs selected by phage display, is tested using a multitarget enzyme-linked immunosorbent assay (ELISA). The ZFPs are applied to microtitre wells coated with streptavidin and a biotinylated target oligonucleotide. After incubation, the wells are washed to remove zinc fingers if they are not adherent to the target sequence, followed by the application of mouse anti-MBP (maltose binding protein) antibody and incubation. Goat anti-mouse antibody coupled to alkaline phosphatase is added and allowed to bind, followed by washing to remove antibody, if it is not bound to zinc fingers. Alkaline phosphatase substrate is added and after stopping the reaction, the optical density at 405 nm (OD405) is determined by spectrophotometry