Post-translational modification

![The genetic code diagram[8] showing the amino acid residues as target of modification.](/uploads/202502/04/GeneticCode22.svg5655.png)
Post-translational modification (PTM) refers to the covalent and generally enzymatic modification of proteins during or after protein biosynthesis. Proteins are synthesized by ribosomes translating mRNA into polypeptide chains, which may then undergo PTM to form the mature protein product. PTMs are important components in cell signaling.