Alternative titles; symbols
HGNC Approved Gene Symbol: ALPG
Cytogenetic location: 2q37.1 Genomic coordinates (GRCh38): 2:232,406,844-232,410,714 (from NCBI)
With monoclonal antibodies, Goldstein et al. (1981) demonstrated a form of alkaline phosphatase seemingly distinct from the placental, intestinal, and liver forms. It was present in trace amounts in testis and thymus. Millan et al. (1982) found that human testes contain trace amounts of heat-stable placentallike alkaline phosphatase. From reactivity with a monoclonal antibody to placental alkaline phosphatase and from study of enzyme inhibitors, they concluded that the testicular enzyme is separate from the placental enzyme.
Millan and Manes (1988) studied the PLAP (171800)-like isozyme called the Nagao isozyme which shows enhanced expression in germ-cell tumors of the testis, especially seminomas, and demonstrated that it is encoded by the germ-cell alkaline phosphatase gene.
Knoll et al. (1988) concluded that 3 closely related alkaline phosphatase genes reside on the long arm of chromosome 2 in man.
Martin et al. (1987) mapped the placentallike alkaline phosphatase gene to 2q37.
Knoll et al. (1988) summarized the 3 closely related alkaline phosphatase genes. One of these genes (the placental ALP1, in their symbology; 171800) encodes the classic heat-stable placental alkaline phosphatase; a second, which they referred to as placental ALP2, 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 (171740). The expression of the intestinal and placental genes is highly tissue-specific in spite of nearly 90% sequence similarity within their exons. Knoll et al. (1988) compared the placental alkaline phosphatase gene with the placentallike gene.
Cloning and sequencing of the placental alkaline phosphatase, intestinal alkaline phosphatase, and germ-cell alkaline phosphatase genes indicated a high degree of homology; in particular, 98% amino acid sequence identity had been demonstrated between placental and germ-cell forms of the enzyme. In a study of a Finnish population, Beckman et al. (1991) described a PstI RFLP strongly correlated with electrophoretic placental alkaline phosphatase types and believed to be caused by a variable restriction site at position 367 in exon 2 of the ALPP gene. However, Beckman et al. (1992) demonstrated that in fact the RFLP involves the germ-cell alkaline phosphatase and that the correlation with the placental alkaline phosphatase type was the result of linkage disequilibrium.
Beckman, G., Beckman, L., Kivela, A., Millan, J. L., Sikstrom, C. A new PstI restriction fragment length polymorphism (RFLP) of placental alkaline phosphatase: RFLP haplotypes and correlation with electrophoretic types. Hum. Hered. 41: 122-128, 1991. Note: Erratum: Hum. Hered. 41: following 350, 1991. [PubMed: 1677344] [Full Text: https://doi.org/10.1159/000153988]
Beckman, G., Beckman, L., Sikstrom, C., Millan, J. L. DNA polymorphism of alkaline phosphatase isozyme genes: linkage disequilibria between placental and germ-cell alkaline phosphatase alleles. Am. J. Hum. Genet. 51: 1066-1070, 1992. [PubMed: 1357964]
Goldstein, D. J., Gogolin, K. J., Harris, H. Possible new locus for alkaline phosphatase in humans. (Abstract) Sixth Int. Cong. Hum. Genet., Jerusalem 1981.
Knoll, B. J., Rothblum, K. N., Longley, M. Nucleotide sequence of the human placental alkaline phosphatase gene: evolution of the 5-prime flanking region by deletion/substitution. J. Biol. Chem. 263: 12020-12027, 1988. Note: Erratum: J. Biol. Chem. 264: 2391 only, 1989. [PubMed: 3042787]
Martin, D., Tucker, D. F., Gorman, P., Sheer, D., Spurr, N. K., Trowsdale, J. The human placental alkaline phosphatase gene and related sequences map to chromosome 2 band q37. Ann. Hum. Genet. 51: 145-152, 1987. [PubMed: 3674755] [Full Text: https://doi.org/10.1111/j.1469-1809.1987.tb01056.x]
Millan, J. L., Eriksson, A., Stigbrand, T. A possible new locus of alkaline phosphatase expressed in human testis. Hum. Genet. 62: 293-295, 1982. [PubMed: 7166303] [Full Text: https://doi.org/10.1007/BF00304541]
Millan, J. L., Manes, T. Seminoma-derived Nagao isozyme is encoded by a germ-cell alkaline phosphatase gene. Proc. Nat. Acad. Sci. 85: 3024-3028, 1988. [PubMed: 2834730] [Full Text: https://doi.org/10.1073/pnas.85.9.3024]