ALPP
Encyclopedia
Alkaline phosphatase, placental type also known as placental alkaline phosphatase (PLAP) is an allosteric enzyme
that in humans is encoded by the ALPP gene
.
), placental (this enzyme), placental-like (ALPPL2), and liver/bone/kidney (ALPL
) (tissue non-specific). The first three are located together on chromosome 2 while the tissue non-specific 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.
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 measure-ment is therefore of little value in this group.
Enzyme
Enzymes are proteins that catalyze chemical reactions. In enzymatic reactions, the molecules at the beginning of the process, called substrates, are converted into different molecules, called products. Almost all chemical reactions in a biological cell need enzymes in order to occur at rates...
that in humans is encoded by the ALPP gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...
.
Gene
There are at least four distinct but related alkaline phosphatases: intestinal (ALPIALPI
Alkaline phosphatase, intestinal also known as ALPI is a type of alkaline phosphatase that in humans is encoded by the ALPI gene....
), placental (this enzyme), placental-like (ALPPL2), and liver/bone/kidney (ALPL
ALPL
Alkaline phosphatase, tissue-nonspecific isozyme is an enzyme that in humans is encoded by the ALPL gene.- External Links :*-Further reading:...
) (tissue non-specific). The first three are located together on chromosome 2 while the tissue non-specific 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 cancerOvarian cancer
Ovarian cancer is a cancerous growth arising from the ovary. Symptoms are frequently very subtle early on and may include: bloating, pelvic pain, difficulty eating and frequent urination, and are easily confused with other illnesses....
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 measure-ment is therefore of little value in this group.