Which amino acids can be methylated?

Methylation involves the addition of methyl groups to proteins. The process of is catalyzed by methyltransferases.

Arginine and lysine are the two major amino acids that can be methylated. Arginine can be methylated once or twice resulting in monomethylated or dimethylated arginine. Lysine can be methylated once, twice or thrice resulting in mono-, di-, or tri-methyl lysine.

Other amino acids that can be methylated include glutamine, histidine, asparagine, cysteine, and glutamate.