You are asked to analyze the amino acid sequence of a peptide PEP of 12 amino ac

You are asked to analyze the amino acid sequence of a peptide PEP of 12 amino acids. You decided to
carry out extensive tryptic cleavage on the peptide first. As a result, two smaller peptides were obtained
and studied individually. (A) For the first peptide (PEP-1), amino acid analysis showed the presence of
only two types of amino acid, valine and arginine. MALDI-TOF of PEP-1 showed a peak at m/z 670.
(B) For the second peptide (PEP-2), after collision induced dissociation (CID), it yielded a mass
spectrum with the first four y-type ions at the following m/z values: 132, 269, 416 and 544. Deduce the
partial sequence of the original peptide PEP.