Solving the Sequence of an Oligopeptide From Sequence Analysis Data Amino acid analy...

Solving the Sequence of an Oligopeptide From Sequence Analysis Data Amino acid analysis of an oligopeptide 7 residues long gave

The following facts were observed:

a. Trypsin treatment had no apparent effect.

b. The phenylthiohydantoin released by Edman degradation was

c. Brief chymotrypsin treatment yielded several products, including a dipeptide and a tetrapeptide. The amino acid composition of the tetrapeptide was Leu, Lys, and Met.

d. Cyanogen bromide treatment yielded a dipeptide, a tetrapeptide, and free Lys.

What is the amino acid sequence of this heptapeptide?