Editing Post-translational modification (section)

== Statistics ==
===Common PTMs by frequency===
In 2011, statistics of each post-translational modification experimentally and putatively detected have been compiled using proteome-wide information from the Swiss-Prot database.<ref>{{cite journal | vauthors = Khoury GA, Baliban RC, Floudas CA | title = Proteome-wide post-translational modification statistics: frequency analysis and curation of the swiss-prot database | journal = Scientific Reports | volume = 1 | issue = 90 | pages = 90 | date = September 2011 | pmid = 22034591 | pmc = 3201773 | doi = 10.1038/srep00090 | bibcode = 2011NatSR...1E..90K }}</ref> The 10 most common experimentally found modifications were as follows:<ref>{{cite web|url=http://selene.princeton.edu/PTMCuration/|title=Proteome-Wide Post-Translational Modification Statistics|website=selene.princeton.edu|access-date=2011-07-22|archive-url=https://web.archive.org/web/20120830234041/http://selene.princeton.edu/PTMCuration/|archive-date=2012-08-30|url-status=dead}}</ref>
{| class="wikitable"
!Frequency
!Modification
|-
|58383
|[[Phosphorylation]]
|-
|6751
|[[Acetylation]]
|-
|5526
|[[N-linked glycosylation]]
|-
|2844
|[[#amidation|Amidation]]
|-
|1619
|[[Hydroxylation]]
|-
|1523
|[[Methylation]]
|-
|1133
|[[O-linked glycosylation]]
|-
|878
|[[Ubiquitin|Ubiquitylation]]
|-
|826
|[[Pyroglutamic acid|Pyrrolidone carboxylic acid]]
|-
|504
|[[Sulfation]]
|}

=== Common PTMs by residue ===
Some common post-translational modifications to specific amino-acid residues are shown below. Modifications occur on the side-chain unless indicated otherwise.

{| class="wikitable sortable" style="text-align: left"   
|-   
! Amino Acid !! Abbrev. !! Modification
|-   
! [[Alanine]]
| Ala or A
| [[Acetylation|N-acetylation]] (N-terminus)
|-   
! [[Arginine]]
| Arg or R
| deimination to [[Citrullination|citrulline]], [[Protein methylation|methylation]]
|-   
! [[Asparagine]]
| Asn or N
| [[deamidation]] to Asp or iso(Asp), [[N-linked glycosylation]], [[Isopeptide bond|spontaneous isopeptide bond formation]]
|-   
! [[Aspartic acid]]
| Asp or D
| [[deamidation|isomerization]] to isoaspartic acid, spontaneous isopeptide bond formation
|-   
! [[Cysteine]]
| Cys or C
| [[disulfide]]-bond formation, oxidation to sulfenic, sulfinic or sulfonic acid, [[palmitoylation]], N-acetylation (N-terminus), [[S-nitrosylation]]
|-   
! [[Glutamine]]
| Gln or Q
| cyclization to [[pyroglutamic acid]] (N-terminus), deamidation to [[glutamic acid]] or [[isopeptide bond]] formation to a [[lysine]] by a [[transglutaminase]]
|-   
! [[Glutamic acid]]
| Glu or E
| cyclization to [[pyroglutamic acid]] (N-terminus), [[gamma-carboxylation]]
|-   
! [[Glycine]]
| Gly or G
| N-[[myristoylation]] (N-terminus), N-acetylation (N-terminus)
|-   
! [[Histidine]]
| His or H
| [[Histidine kinase|phosphorylation]]
|-   
! [[Isoleucine]]
| Ile or I
|
|-   
! [[Leucine]]
| Leu or L
|
|-   
! [[Lysine]]
| Lys or K
| [[acetylation]], [[ubiquitylation]], [[SUMO protein|SUMOylation]], [[Protein methylation|methylation]], [[hydroxylation]] leading to [[allysine]], spontaneous isopeptide bond formation
|-   
! [[Methionine]]
| Met or M
| N-acetylation (N-terminus), N-linked ubiquitination, oxidation to [[sulfoxide]] or [[sulfone]]
|-   
! [[Phenylalanine]]
| Phe or F
|
|-   
! [[Proline]]
| Pro or P
| [[hydroxylation]]
|-   
! [[Serine]]
| Ser or S
| [[phosphorylation]], [[O-linked glycosylation]], N-acetylation (N-terminus)
|-   
! [[Threonine]]
| Thr or T
| phosphorylation, O-linked glycosylation, N-acetylation (N-terminus)
|-   
! [[Tryptophan]]
| Trp or W
| mono- or di-oxidation, formation of [[kynurenine]], [[tryptophan tryptophylquinone]]
|-   
! [[Tyrosine]]
| Tyr or Y
| [[Tyrosine sulfation|sulfation]], phosphorylation
|-   
! [[Valine]]
| Val or V
| N-acetylation (N-terminus)
|}