Chapter 6, Problem 6.36P

Interpretation Introduction

Interpretation:

Isoelectric point-pI value for glutamic acid is to be computed. To which terminal will the glutamic acid migrate in an electrophoresis with gel of pH $7$ is to be explained.

Concept introduction:

Isoelectric point (pI) or isoelectric pH is the pH at which the substance has zero charge. Amino acid’s pI is the average of two pKa values involving zwitterions formation.

If the pH of the solution is higher than pI, the substance will deprotonate and will carry negative charge. Conversely, if the pH is lower than pI, the substance will protonate and will carry a positive charge.

Any ion that has net positive charge (cations) will migrate toward the negatively charged terminal i.e. cathode, and the ion with negative charge (anions) will migrate toward positively charged terminal i.e. anode.