Secreted embryonic alkaline phosphatase (SEAP)

Secreted embryonic alkaline phosphatase (SEAP) is a truncated, recombinant version of human placental alkaline phosphatase (PLAP) that has been engineered for secretion into the extracellular environment. Unlike the wild-type enzyme, which is membrane-bound via a glycosylphosphatidylinositol (GPI) anchor, SEAP lacks the C-terminal anchoring domain, allowing for non-invasive monitoring of its activity in cell culture supernatants or body fluids. It is widely utilized as a reporter gene in biotechnology and drug discovery to quantify gene expression, promoter activity, and the activation of signaling pathways such as the NF-κB pathway. SEAP is characterized by its high thermal stability and resistance to the inhibitor L-homoarginine, properties that enable researchers to distinguish its activity from endogenous alkaline phosphatase background. While not a direct therapeutic target, its parent molecule, PLAP, is a well-known biomarker for certain cancers, including germ cell tumors and ovarian carcinoma, and is being explored as a target for antibody-based and CAR-T cell therapies.

Other names

SEAPSecreted placental alkaline phosphataseTruncated placental alkaline phosphataseSecreted human placental alkaline phosphatase

Not applicable as a therapeutic target; functions as a reporter enzyme by hydrolyzing phosphate substrates to produce a detectable colorimetric, fluorescent, or chemiluminescent signal.