Alkaline phosphatase is widely used in ELISA for conjugation with secondary antibody or streptavidin. The SensoLyteŽ pNPP Alkaline Phosphatase ELISA Assay Kit is optimized to detect alkaline phosphatase (AP) conjugated secondary antibody or streptavidin in ELISA. pNPP is a colorimetric substrate for alkaline phosphatase and the absorbance can be monitored at 405 nm. The kit provides ample material to perform 500 assays in a 96-well format. The alkaline phosphatase conjugated rabbit anti-goat IgG is included in the kit. The protocol can readily be modified to run assays in a 384-well format.