Biochemistry 6th Edition by Reginald Garrett,Charles Grisham

Exercise 3

Solving the sequence of an oligopeptide from sequence analysis data
Amino acid analysis of a decapeptide revealed the presence of the following products:
The following facts were observed:
a. Neither carboxypeptidase A or B treatment of the decapeptide had any effect.
b. Trypsin treatment yielded two tetrapeptides and free Lys.
c. Clostripain treatment yielded a tetrapeptide and a hexapeptide.
d. Cyanogen bromide treatment yielded an octapeptide and a dipeptide of sequence NP (using the one-letter codes).
e. Chymotrypsin treatment yielded two tripeptides and a tetrapeptide. The N-terminal chymotryptic peptide had a net charge of -1 at neutral pH and a net charge of -3 at pH 12.
f. One cycle of Edman degradation gave the PTH derivative:

What is the amino acid sequence of this decapeptide?