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Alkaline phosphatase, placental type

protein-coding gene in the species Homo sapiens

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Record originEnglish Wikipedia
Text licenseCC BY-SA 4.0
Source revisionSep 21, 2026
Entity authorityQ15997033 ↗
Source-derived summary

Alkaline phosphatase, placental type also known as placental alkaline phosphatase (PLAP) is an allosteric enzyme that in humans is encoded by the ALPP gene.

Gene

There are at least four distinct but related alkaline phosphatases: intestinal (ALPI), placental (this enzyme), placental-like (ALPPL2), and liver/bone/kidney (ALPL) (tissue-nonspecific). The first three are located together on chromosome 2, whereas the tissue-nonspecific form is located on chromosome 1. The coding sequence for this form of alkaline phosphatase is unique in that the 3' untranslated region contains multiple copies of an Alu family repeat. In addition, this gene is polymorphic and three common alleles (type 1, type 2, and type 3) for this form of alkaline phosphatase have been well-characterized.

Function

Alkaline phosphatase, placental type is a membrane-bound glycosylated dimeric enzyme, also referred to as the heat-stable form, that is expressed primarily in the placenta, although it is closely related to the intestinal form of the enzyme as well as to the placental-like form.

Clinical significance

PLAP is a tumor marker, especially in seminoma and ovarian cancer (e.g., dysgerminoma). PLAP is reliable only in non-smokers, as smoking interferes with measurement of PLAP, since serum concentrations of PLAP are increased up to 10-fold in smokers and its measurement is therefore of little value in this group.

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The public source identifies “Alkaline phosphatase, placental type” as protein-coding gene in the species Homo sapiens. This brief keeps that definition visible, then builds a research path around Alkaline, phosphatase and placental.

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Datasets, specimens, observations and peer-reviewed methods provide the appropriate test for the technical claims summarized here. The source revision retrieved here is dated Sep 21, 2026. The linked authority identifier is Q15997033. None of the 0 selected statements returned an explicit reference.

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This entry incorporates text from “Alkaline phosphatase, placental type” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.