6.III: Protein sequencing. Last updated Save as PDF Page ID7271 A. Sanger's reagent, FDNB (fluorodinitrobenzene), modifies N-terminus for determination via amino acid analysis. B. Edman degradation. Uses PITC (phenylisothiocyanate) to sequentially remove N-terminal amino acids for analysis. PITC can be used to sequentially remove and analyze amino acids from a polypeptide on solid support.