title: Phospholipase resistance of the glycosyl-phosphatidylinositol membrane anchor on human alkaline phosphatase.
abstract: Alkaline phosphatase (ALP) is attached to the cell surface in mammalian tissues via a glycosyl-phosphatidylinositol (GPI) anchor and can be released from the membrane by GPI-specific phospholipases. In a range of cultured human cell lines, however, the sensitivity of ALP to phospholipases was observed to be variable in magnitude (approximately 20-90%). The mechanism of phospholipase resistance was explored with phospholipases of different bond specificities. The results suggest that phospholipase resistance is the result of acylation of the inositol ring in the GPI anchor. The occurrence of phospholipase-resistant forms of ALP may have important implications for the in vivo release and disposition of plasma ALP.
authors.affiliation: Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons of Columbia University, New York, NY 10032.
authors.forename: Y W
authors.initials: YW
authors.lastname: Wong
authors.forename: M G
authors.initials: MG
authors.lastname: Low
mesh_terms: D000215:Acylation; D000469:Alkaline Phosphatase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D000440:Butanols; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology*; D004790:Enzyme Induction; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D006367:HeLa Cells / Q000201:enzymology; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D043265:Phosphatidylinositol Diacylglycerol-Lyase; D010739:Phospholipase D / Q000378:metabolism; D010740:Phospholipases / Q000378:metabolism*; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D051381:Rats; D013379:Substrate Specificity
chemical_list: D000440:Butanols; D017261:Glycosylphosphatidylinositols; D010740:Phospholipases; D000469:Alkaline Phosphatase; D010727:Phosphoric Diester Hydrolases; D010739:Phospholipase D; C065017:glycoprotein phospholipase D; D043265:Phosphatidylinositol Diacylglycerol-Lyase