Question

Three peptides were obtained from a trypsin digestion of two different polypeptides. Indicate the possible sequences from the given data.

1. Val-Gly-Arg

2. Ala-Val-Lys

3. Ala-Gly-Phe

Answer 1

Trypsin is generally produced as inactive trypsinogen form in pancreas. Once trypsinogen is secreted into the small intestine the enzyme enteropeptidase activates trypsinogen into trypsin by proteolytic clevage. Trypsin catalyses the hydrolysis of peptide bonds, breaking down protiens into smaller peptides. trypsin generally cleaves peptide chains at carboxyl side of the amino acids lysine and arginine, this process generally called as trypsin proteolysis or trypsinisation.

The possible sequences of polypeptide could be as follows.

1) Val-Gly-Arg-Ala-Val-Lys-Ala-Gly-Phe

2) Ala-Val-Lys-Val-Gly-Arg-Ala-Gly-Phe