A pentapeptide has the following proportions of amino acids: gly (1), leu (1), val (1), phe (2). Treatment of the pentapeptide with chymotrypsin gave the following fragments: gly-val, leu, phe. Which is the structure of the pentapeptide?

Question

Quizplus · Accepted Answer

Since chymotrypsin cleaved after aromatic amino acids (Phe), the first cleavage would be between the two Phe residues, resulting in two fragments: Phe and Gly-Val-Leu-Phe. The second cleavage would take place after Leu, resulting in two fragments: Leu and Gly-Val-Phe-Phe. Therefore, the structure of the pentapeptide must be Leu-Gly-Val-Phe-Phe. The only option that matches this structure is choice C.

A Pentapeptide Has the Following Proportions of Amino Acids: Gly