Antibody and streptavidin conjugates of alkaline phosphatase are extensively used as detection reagents in ELISA. The SensoLyte® pNPP Alkaline Phosphatase ELISA Assay Kit provides a sensitive chromogenic substrate for quantifying alkaline phosphatase activity in ELISA. The kit contains: pNPP chromogenic liquid substrate (absorption maximum = 405 nm upon dephosphorylation), Assay buffer, ELISA wash buffer, Stop solution, Alkaline phosphatase conjugated secondary antibody (goat anti-rabbit IgG), an optimized ELISA assay protocol.