Chapter 25, Problem 50PP

Interpretation Introduction

Interpretation:

The amino acid residues present in lysozyme and pepsin need to be found out.

Concept introduction:

Amino acids at a particular pH do not migrate in an electric field.  This pH is known as the isoelectric point.  The isoelectric point is also known as isoionic point.  At this isoelectric point the amino acid is neutral.  This means that the zwitterion form predominates more over the other forms.  pI is the isoelectric point and this can be given by average of the pK_a.

$\text{pI=}\frac{{\text{pK}}_{{\text{a}}_{\text{1}}}{\text{+pK}}_{{\text{a}}_{\text{2}}}}{\text{2}}$

The amino acid which has more acidic groups is said to have lower pI value and the compound which has more basic groups is said to have higher pI value.

To find : To find the amino acid residues present in lysozyme and pepsin