A sample of unknown peptide was treated with trypsin; another sample of the same

Question

A sample of unknown peptide was treated with trypsin; another sample of the same peptide was treated with chymotrypsin. The sequences (N-terminal to C-terminal) of the smaller peptides produced by trypsin digestion were as follows: Met-Val-Ser-Thr-Lys Val-lle-Trp-Thr-Leu-Met-lle Leu-Phe-Asn-Glu-Ser-Arg The sequences of the smaller peptides produced by chymotrypsin digestion were as follows Asn-Glu-Ser-Arg-Val-lle-Trp Thr-Leu-Met-lle Met-Val-Ser-Thr-Lys-Leu-Phe Deduce the sequence of the original peptide.

Explanation / Answer

The sequence of the peptide is

Met- Val-ser-Thr-Lys-Leu-Phe-Asn-Glu-Ser-Arg-Val-LLe-Trp-Thr-Leu-Met-LLe.

It is determined based on overlapping sequences. In chymotrypsin digestion after lys leu is present hence fraction 3 of trypsin comes after 1st one again after arg in the third fragment of trypsin digestion val is present in chymotripsin digested fragment hence fragment two comes after 2nd one in trypsin digestion.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.