Chapter 23, Problem 23.76SP

Interpretation Introduction

Interpretation:

The amino acids in the given hexapeptide should be identified.

Concept introduction:

Amino acids are the molecules containing an amine group, a carboxylic group, and a side-chain that is specific to each amino acid. They are the basic structural building units of protein and other biomolecules.

Carbon, hydrogen, oxygen and nitrogen are the key elements in amino acid.

General structure of an amino acid can be drawn as follows,

The amino acids are distinguished from one another by their R group also known as a side chain.

Some amino acids are listed below,

$\begin{array}{cc}\text{Name}\text{of}\text{amino}\text{acid}& \text{Side}\text{chain}\text{(R)}\\ \text{Threonine}& \text{Secondary alcohol}\\ \text{Valine}& \text{Isopropyl}\text{group}\\ Methionine& \text{Thiol}\left({\text{-CH}}_{\text{2}}{\text{CH}}_2{\text{SCH}}_{\text{3}}\right)\\ \text{Alanine}& Methyl\left(-C{H}_3\right)\\ \text{Serine}& {\text{Alcohol(-CH}}_{\text{2}}\text{OH)}\\ \text{Phenylalanine}& \text{Aromatic}\text{ring}\left({\text{C}}_{\text{6}}{\text{H}}_{\text{5}}{\text{CH}}_{\text{2}}\right)\end{array}$

Peptide is a short polymer of amino acids joined by peptide bonds and they are classified by the number of amino acid in the chain and so a hexapeptide contains six amino acids and are joined by peptide bonds.

Peptide bonds are formed by a condensation reaction of carboxylic group of an amino acid and amino group of another amino acid with the removal of water molecule.