Guanidinylated is a term derived from guanidine, a compound that contains a nitrogen atom with bonding electrons that can form a bond with a carbonyl group. Synonyms for guanidinylated include guanidination, guanidylation, and guanidylation modification. These terms refer to chemical reactions that introduce a guanidine group into a molecule or modify an existing amino acid residue to become guanidinated. Other synonyms for guanidinylated include arginine modification or arginine methylation, as guanidinated amino acid residues are typically found on arginine side chains. These modifications are common in biochemistry and can affect protein structure, function, and cellular signaling.