Question

What are the products from treatment of the following peptide with chymotrypsin? Met-Tyr-Pro-Ser-Phe-Val-Lys-Asn-His-Tyr-Gly-Arg-Met-Trp

a) Met-Tyr
b) Pro-Ser-Phe
c) Val-Lys-Asn
d) His-Tyr-Gly-Arg-Met-Trp

Answer 1

The peptide Met-Tyr-Pro-Ser-Phe-Val-Lys-Asn-His-Tyr-Gly-Arg-Met-Trp treated with chymotrypsin will yield fragments: Met-Tyr, Pro-Ser-Phe, His-Tyr-Gly-Arg-Met, with the final fragment being Trp, after cleavage at specific aromatic amino acids.

Step-by-step explanation:

The student's question involves identifying the products of a peptide (Met-Tyr-Pro-Ser-Phe-Val-Lys-Asn-His-Tyr-Gly-Arg-Met-Trp) upon treatment with the enzyme chymotrypsin. Chymotrypsin is a proteolytic enzyme that cleaves peptides at the carboxyl side of aromatic amino acids, which include phenylalanine, tyrosine, and tryptophan. Given this specificity, the peptide fragments resulting from the cleavage by chymotrypsin would be:

• Met-Tyr (cleavage after Tyrosine)
• Pro-Ser-Phe (cleavage after Phenylalanine)
• Val-Lys-Asn (no cleavage, as there are no aromatic residues for chymotrypsin to act on)
• His-Tyr-Gly-Arg-Met (cleavage after Tyrosine and before Tryptophan)
• Trp (remaining peptide fragment)