Addition by an enzyme in vivo Hydrophobic groups for membrane localization •
myristoylation (a type of
acylation), attachment of
myristate, a C14 saturated acid •
palmitoylation (a type of acylation), attachment of
palmitate, a C16 saturated acid •
isoprenylation or
prenylation, the addition of an
isoprenoid group (e.g.
farnesol and
geranylgeraniol) •
farnesylation •
geranylgeranylation •
glypiation,
glycosylphosphatidylinositol (GPI) anchor formation via an amide bond to C-terminal tail
Cofactors for enhanced enzymatic activity •
lipoylation (a type of acylation), attachment of a
lipoate (C8) functional group •
flavin moiety (
flavin mononucleotide (FMN) or
flavin adenine dinucleotide (FAD)) may be covalently attached •
heme C attachment via
thioether bonds with
cysteines •
phosphopantetheinylation, the addition of a 4'-phosphopantetheinyl moiety from
coenzyme A, as in fatty acid, polyketide, non-ribosomal peptide and leucine biosynthesis •
retinylidene Schiff base formation
Modifications of translation factors •
diphthamide formation (on a histidine found in
eEF2) •
ethanolamine phosphoglycerol attachment (on glutamate found in
eEF1α) •
hypusine formation (on conserved lysine of
eIF5A (eukaryotic) and
aIF5A (archaeal)) •
beta-Lysine addition on a conserved lysine of the
elongation factor P (EFP) in most bacteria. EFP is a homolog to
eIF5A (eukaryotic) and
aIF5A (archaeal) (see above).
Smaller chemical groups in PTM •
acylation, e.g.
O-acylation (
esters),
N-acylation (
amides),
S-acylation (
thioesters) •
acetylation, the addition of an
acetyl group, either at the
N-terminus of the protein or at
lysine residues. The reverse is called
deacetylation. •
formylation •
alkylation, the addition of an
alkyl group, e.g.
methyl,
ethyl •
methylation the addition of a
methyl group, usually at
lysine or
arginine residues. The reverse is called
demethylation. • amidation at C-terminus. Formed by oxidative dissociation of a C-terminal Gly residue. •
monoaminylation, addition of
monoamines to
glutamine residues via
transamidation •
dopaminylation, the addition of
dopamine to
glutamine residues via
transamidation •
histaminylation, the addition of
histamine to
glutamine residues via
transamidation •
serotonylation, the addition of
serotonin to
glutamine residues via
transamidation •
amide bond formation •
amino acid addition •
arginylation, a
tRNA-mediation addition •
polyglutamylation, covalent linkage of
glutamic acid residues to the N-terminus of tubulin and some other proteins. (See
tubulin polyglutamylase) •
polyglycylation, covalent linkage of one to more than 40
glycine residues to the
tubulin C-terminal tail •
butyrylation •
gamma-carboxylation dependent on
Vitamin K •
glycosylation, the addition of a
glycosyl group to either
arginine,
asparagine,
cysteine,
hydroxylysine,
serine,
threonine,
tyrosine, or
tryptophan resulting in a
glycoprotein. Distinct from
glycation, which is regarded as a nonenzymatic attachment of sugars. •
paucimannosylation, addition of simple glycans, primarily containing mannose and N-acetylglucosamine (GlcNAc), to asparagine residues •
O-GlcNAc, addition of
N-acetylglucosamine to serine or threonine residues in a β-glycosidic linkage • polysialylation, addition of
polysialic acid (PSA) to
neural cell adhesion molecule (NCAM) •
hydroxylation: addition of an oxygen atom to the side-chain of a Pro or Lys residue •
iodination: addition of an iodine atom to the aromatic ring of a tyrosine residue (e.g. in
thyroglobulin) •
nucleotide addition such as
ADP-ribosylation •
persulfidation, the addition of a sulfur molecule onto a
thiol group of a
cysteine residue •
phosphate ester (
O-linked) or
phosphoramidate (
N-linked) formation •
phosphorylation, the addition of a
phosphate group, usually to
serine,
threonine, and
tyrosine (
O-linked), or
histidine (
N-linked) •
adenylylation, the addition of an
adenylyl moiety, usually to
tyrosine (
O-linked), or
histidine and
lysine (
N-linked) • uridylylation, the addition of an uridylyl-group (i.e.
uridine monophosphate (UMP)), usually to tyrosine •
propionylation •
pyroglutamate formation •
S-glutathionylation •
S-nitrosylation •
S-sulfenylation (
aka S-sulphenylation), reversible covalent addition of one oxygen atom to the
thiol group of a
cysteine residue •
S-sulfinylation, normally irreversible covalent addition of two oxygen atoms to the
thiol group of a
cysteine residue •
carbamylation the addition of
Isocyanic acid to a protein's N-terminus or the side-chain of Lys. •
carbonylation the addition of carbon monoxide to other organic/inorganic compounds. •
glycation, the addition of a sugar molecule to a protein without the controlling action of an enzyme. •
glutarylation, the addition of a glutaryl group to lysine residues •
malonylation, the addition of a malonyl group to lysine residues •
methylmalonylation, the addition of a methylmalonyl group to lysine residues • spontaneous
isopeptide bond formation, between lysine and aspartic acid or asparagine, as found in many surface proteins of
Gram-positive bacteria. •
succinylation, addition of a
succinyl group to
lysine Non-enzymatic additions in vitro •
biotinylation: covalent attachment of a biotin moiety using a biotinylation reagent, typically for the purpose of labeling a protein. • carbamylation: the addition of isocyanic acid to a protein's N-terminus or the side-chain of Lys or Cys residues, typically resulting from exposure to urea solutions. • oxidation: addition of one or more oxygen atoms to a susceptible side-chain, principally of Met, Trp, His or Cys residues. Formation of
disulfide bonds between Cys residues. •
pegylation: covalent attachment of
polyethylene glycol (PEG) using a pegylation reagent, typically to the N-terminus or the side-chains of Lys residues. Pegylation is used to improve the efficacy of protein pharmaceuticals. ==Conjugation with other proteins or peptides==