Related: Biological Science MOC
Edman degradation = amino acids in a polypeptide/protein chain are taken off one by one from the N-terminus of the chain
- they can “break off” from the chain because the terminus end can be modified by phenylisothiocyanate (PITC). PITC modifies the free alpha-amino group to the point where it can be cleaved off via an acid.
- the released amino acid is then characterized via its elution profile using high-performance liquid chromatography
- this is a column chromatography method!
- after the amino acid is cleaved, the terminus returns to a normal amino group. so if you want to keep going, you need to repeat the edman degradation
Potential issues
- alpha terminus is blocked: if the alpha terminus has been chemically modified by other chemical groups (formyl/acetyl groups), edman degradation will not work/not work well
- potential solution: you can try to digest the protein with a protease and then sequence it. this could leave off a bit of the end of the peptide chain/some amino acids, though it might be better than nothing
references/links
- Molecular Biology of the Gene, Watson, 7e
- Protein Sequencing Service by Edman Degradation | MtoZ Biolabs