Chapter 5, Problem 14RQ

Summary Introduction

To review:

The structure and the net charge on amino acid arginine at the given pH (potential of hydrogen) value of 1, 4, 7, 10, and 12 is to be given. The given $\text{p}{K}_{\text{a}}$ (negative logarithm of the dissociation constant) values are $\text{p}{K}_1$ =2.17, $\text{p}{K}_2$ =9.04, and $\text{p}{K}_{\text{R}}$ =12.48.

Introduction:

Arginine is a basic polar amino acid. It containsan amino group ( ${\text{-NH}}_{\text{2}}$ ), acarboxylic group (-COOH), and a side chain consisting of 3-carbon chain with a guanidine group( ${\text{-C-(NH}}_{\text{2}}{\text{)}}_{\text{2}}{}^{\text{+}}$ ). This guanidine group consists of two amino groups that are responsible for the basic nature of arginine. The isoelectric point of the amino acid is the pH (potential of hydrogen) at which there is no net charge.