Question

Determine the amino acid sequence of a polypeptide from the following data:

Answer 1

Solution :

1. It is given that when Edman's reagent is used, it releases PTH-Glycin. The degradation of Edmans is used for the amino acids to sequencing of the peptide/protein and is also removes N terminal amino acid and thus gives us the PTH amino acid product.

Therefore, the first amino acid is Glycine.

2. The Carboxypeptidase A releases the C terminal amino acid, and therefore the last amino acid is Phe.

3. The Cyanogen Bromide helps to chop after the Med residue, therefore the sequence is 1 - 2 - 3 or 2 - 1 - 3.

4. The trysin chops after the basic amino acid - Arg and the Lys unless followed by Proline and so the sequence of the peptide is 1 - 2 - 3 4.