Glycosylphosphatidylinositol

**Semantic type:** Biologically Active Substance|Organic Chemical

**Definition:** A glycolipid that functions as a protein modifier and has a core structure composed of a phosphatidylinositol (PI) bound, through a carbohydrate linker comprised of glucosamine and three mannose residues, to an ethanolamine phosphate (EtNP), which can be covalently linked to the carboxy-terminal amino acid of the modified protein. Glycosylphosphatidylinositol moieties anchor extracellular proteins to the cell surface by insertion of the PI fatty acid chains into the membrane bilayer.

**Synonyms:** - GPI