Sanger's reagent is

Sanger's reagent or di-nitro-fluoro-benzene (DNFB) is used for polypeptide sequencing. Other methods of Polypeptide sequencing: Edman's degradation (Edman's reagent is Phenyl-isothiocyanate) - Determine sequence from N-terminal end and can sequence 30-60 amino acid residues. But it cannot work if N-terminal amino acid is chemically modified. Use of various chemical or enzymes to cleave peptides - method used for large polypeptides Mass spectrometry - 3 pas of mass spectrometer are ionization source, mass analyzer and ion detector.