Alkaline Phosphatase, Placental Like Protein 2 (ALPPL2)

Cloning and sequencing of the placental alkaline phosphatase, intestinal alkaline phosphatase, and germ-cell alkaline phosphatase genes indicate a high degree of homology; in particular, 98% amino acid sequence identity has been demonstrated between placental and germ-cell forms of the enzyme.

ALPPL1 encodes the classic heat-stabile placental alkaline phosphatase; ALPPL2 is closely related to the first, and may encode the so-called placental ALP-like enzyme of the testis and thymus; the third member of this gene family, the intestinal ALP gene, encodes intestinal alkaline phosphatase. The expression of the intestinal and placental genes is highly tissue-specific in spite of nearly 90% sequence similarity within their exons.