Chapter 26, Problem 33P

Interpretation Introduction

Interpretation: Among the given protonated form of the histidine residue, A or B, the more stable form has to be identified.

Concept introduction:

The organic compounds that contain amine $\left({\text{-NH}}_{\text{2}}\right)$ and carboxyl $\left(\text{-COOH}\right)$ functional groups with a side chain $\left(\text{-R}\right)$ are known as amino acids.

Amino acids consist of both positive as well negative groups in their structure and are called as ampholytes.

The organic compounds that consist of a cyclic and planar ring structure with alternate single and double bonds are called as aromatic compounds.

Aromatic compounds follow the Huckel $\left(4n+2\right)$ rule of aromaticity that is the compound has $4n+\text{2 }\pi$ electrons.