Chapter 16.5, Problem 16.12P

(a)

Interpretation Introduction

Interpretation:

Four amide bonds in $\text{met-enkephalin}$ has to be labeled.

Concept Introduction:

Peptides are compounds that consist of amide linkage and formed when carboxylic acid group of one unit of amino acid reacts with amine group of another amino acid. The amide linkage is also therefore known as peptide linkage. Peptide linkage contains two terminals. One is $\text{N-terminal}$ that is $\text{α}$ carbon with free $-{\text{NH}}_3^{+}$. Other is $\text{C-terminal}$ that is $\text{α}$ carbon with free $-{\text{COO}}^{-}$.

(b)

Interpretation Introduction

Interpretation:

Name of $\text{N-terminal}$ amino acid present in both enkephalins has to be labeled.

Concept Introduction:

Refer to part (a).