thumb|220px|left|Fig. 3 C-terminal amidation amination (see Figure) The C-terminus can also be blocked (thus, neutralizing its negative charge) by amination. glycosyl phosphatidylinositol (GPI) attachment Glycosyl phosphatidylinositol(GPI) is a large, hydrophobic phospholipid prosthetic group that anchors proteins to cellular membranes. It is attached to the polypeptide C-terminus through an amide linkage that then connects to ethanolamine, thence to sundry sugars and finally to the phosphatidylinositol lipid moiety.
Th!umb|220px|lEFt|fig. 3 c-teRMina:l amIdAtIon aminaTiON (see figure) tHe C-Terminus CAn Also bE blocked (tHuS, neuTraliziNg its nEgAtive ChaRGe) by amInAtiON. glycOsyl phOspHatidylinosIToL (Gpi) attaChmEnt glYcosYl pHOSphaTIdYlinoSiToL(gpI) IS a large, HyDrOpHobic p.hospHolipid PrOsThetIc Group ?that aNChors PRoteinS to CelluLAR mEMbraNEs. It iS attaCHEd To The pOLypeptide c-termInuS thRougH An AMide LInKage tHat thEN coNnects to eThAnOlAMINe, Thence to SUNdry sUgaRS and finally to the PhOSPhaTIDYlinosITOL lIpId moIetY.