Application of chemical selective cleavage methods to analyze post-translational modification in proteins

Three chemical specific cleavage reactions, one for the carboxyl side of as partyl peptide bonds, one for the carboxyl side of asparaginyl peptide bond s and another for the amino side of seryl/threonyl peptide bonds have been recently established. Additionally, these reactions simultaneously react on several post-translationally modified groups in peptides or proteins. The modified groups cover the external modifications N-formyl, N-acetyl, N-pyro glutamyi residues and C-terminal-alpha amide, as well as the internal modif ications such as O-acetyl serine, phosphorylated serine/tyrosine, sulfonyla ted tyrosine, glycosylated serine/threonine and glycosylated asparagine. Th ese three cleavage reactions relate to key amino acids for modifications, d eamidation for asparagine, phosphorylation and acetylation for serine, and glycosylation for asparagine, serine and threonine. The chemical reactions on these modifications change the peptide mapping pattern, and information from these reactions may contribute characterization and location of post-t ranslational modified groups in the protein.