The main post-translational modifications are:

-       Phosphorylation (Ser, Thr, or Tyr: important in the transduction of signals across membranes.

-       The removal of the formyl-methionine or methionine by a specific enzyme (Met - aminopeptidase : MAP)is more than 50% of the proteins of the two cell types. The N-formyl the first methionine is removed in E. coli by a formylase.

-       Cleavage of chain polypeptide (Ex. Insulin)

-       Glycosylation

-       Addition of lipids

-       Formation of disulfide bridges or bridge covalent (elastin, collagen).

-       Acetylation (≈100protéinescytoplasmiqueontunN-terminal acetylated), the reaction is catalyzed by N-α - acetyl transferase (example: histone acetylation).

-       Hydroxylation (hydroxylation of proline and lysine)

-       Biotinylation : Addition of biotin [vitB8] (coenzyme of some enzymes of carboxylation [transfer of CO2]).

-Elimination of sequences on cash at the protein level, this process is called splicing, protein and peptide eliminated is named intein.

Figure 18 : The major post-translational modifications.