Edman Degredation

Edman Degredation

1. PROCEDURE

   • Phenlisothiocyonate
     • +(mildly alk cdns)
     • uncharged terminal amino group
       • =cyclical phenylthiocarbamoyl derivative.
         • under acidic cdns
           • cleaved as a thiazolinone derivative.
             • the aa is selectively extracted into an org solve. and treated with acid to form the more stable phenylthiohydantoin (PTH)- AA
               • pth aa can be identified using electrophori or chrome.
                 • Procedure can be preheated again to identify next aa

2. HISTORY

   • Edman degradation (Pehr Edman), is a method of sequencing AAs in a peptide. The amino-terminal residue is labeled and cleaved from the peptide without disrupting the peptide bonds between other amino acid residues.

3. DISADVANTAGES

   • peptides being seq can't have more than 50-60 residues
   • due to the cyclical derivatization not always going to completion
   • resolved by: cleaving large peptides into smaller peptides before proceeding with the reaction.

4. ADVANTAGES

   • it only uses 10 - 100 pico-moles of peptide for the sequencing process.