B. Edman Degradation sequencing:  Edman Degradation sequencing methods is given Figure 38.4 and it has following steps:

1. Similar to sanger reagent, phenylisothiocynate reacts with the terminal amino group to form a cyclic phenylthiocarbamoyl derivative.

2. Under acidic condition, the terminal amino acid is cleaved from the main chain as thiazolinone derivative.

3. Thizolinone derivative is extracted into the organic solvent and it forms phenylthiohydantoin-amino acid (PTH-amino acid) derivative in the presence of acid.

4. PTH-amino acid acid complex can be identify by HPLC or TLC and comparison with the standard amino acids. 

5. Step 1-4 can be repeated again with the next amino acid residue in the peptide chain.

Figure 38.4: Steps in Edman degradation method of protein sequencing.