The secreted alkaline phosphatase (SEAP) is widely used as reporter gene to analyze gene expression, the activity of promoters and transcriptional factors in cell culture or animals. SEAP can be effectively secreted into culture medium and serum. This unique characteristic of SEAP makes it convenient for kinetic analysis of gene expression over a period of time. SensoLyte® pNPP Secreted Alkaline Phosphatase Reporter Gene Assay Kit provides a sensitive colorimetric assay of placental alkaline phosphatase for both secreted and membrane-bound form of enzyme. The kit contains: pNPP chromogenic liquid substrate (absorption maximum = 405 nm upon dephosphorylation), Assay buffer, Stop solution, Placental alkaline phosphatase standard, “mix and read” assay protocol that is compatible with high throughput screening.