Editing C-terminus (section)

===C-terminal modifications===
The C-terminus of proteins can be modified [[posttranslational modification|posttranslationally]], most commonly by the addition of a [[lipid]] anchor to the C-terminus that allows the protein to be inserted into a membrane without having a [[transmembrane domain]].

====Prenylation====
{{main|Prenylation}}
One form of C-terminal modification is [[prenylation]]. During prenylation, a [[Farnesyl pyrophosphate|farnesyl]]- or [[Geranylgeranyl pyrophosphate|geranylgeranyl]]-isoprenoid membrane anchor is added to a [[cysteine]] residue near the C-terminus. Small, membrane-bound [[G protein]]s are often modified this way.{{cn|date=April 2024}}

====GPI anchors====
{{main|Glycosylphosphatidylinositol}}
Another form of C-terminal modification is the addition of a phosphoglycan, [[glycosylphosphatidylinositol]] (GPI), as a membrane anchor. The GPI anchor is attached to the C-terminus after proteolytic cleavage of a C-terminal propeptide. The most prominent example for this type of modification is the [[prion]] protein.

====Methylation====
{{See also|Methylation#In biology|l1=Methylation|(Phosphatase 2A protein)-leucine-carboxy methyltransferase}}
C-terminal [[leucine]] is methylated at carboxyl group by enzyme [[leucine carboxyl methyltransferase 1]] in vertebrates, forming [[methyl ester]].<ref>{{cite web|url=https://www.rhea-db.org/rhea/48544|title=RHEA:48544|publisher=[[Swiss Institute of Bioinformatics]]}}</ref>