Chapter 5, Problem 32CQ

Summary Introduction

To determine: The sequence of the intact peptide.

Concept introduction: Proteins are made up of one or more amino acids linked together to form a chain. The building blocks of the protein is called amino acid. Amino acids are termed as residues if they release a hydrogen ion from the amine end or a hydroxyl ion from the carboxyl end, or both; a water molecule is released as a result of formation of each amide bond. When more than eight peptides are linked together by peptide bonds, it forms a polypeptide.

Given:

• Cleavage with cyanogen bromide (CNBr) yields three smaller peptides: Arg-Ala-Tyr-Gly-Asn, Leu-Phe-Met, Asp-Met.
• Cleavage with chymotrypsin yields three peptides: Met-Arg-Ala-Tyr, Asp-Met-Leu-Phe, Gly-Asn.