Dear
The pH at which the net charge of the solute (amino acid) is neutral is called the isoelectric point.
At a pH below a molecule's pI, that molecule will carry a net positive charge; at a pH above its pI, the molecule will carry a net negative charge.
Therefore, it is expected that the oxidizing potential will be different at different pHs due to the change in the form of the amino acid (neutral, cationic, anionic).
In a method called isoelectric focusing, proteins are run through a gel that has a pH gradient. The gels are set in a buffer in a container with a negatively charged electrode (cathode) on one end and a positively charged electrode (anode) on the other. When the proteins are added to the solution and current is applied, they migrate toward the electrode with the opposite charge. For example, a protein that is in a pH region below its isoelectric point will be positively charged and so will migrate towards the cathode (negative charge). As it migrates through a gradient of increasing pH, however, the protein's overall charge will decrease until the protein reaches the pH region that corresponds to its pI. At this point, it has no net charge, and so it stops moving in the gel. The proteins become focused into sharp stationary bands with each protein positioned at a point in the pH gradient corresponding to its pI. This technique is capable of extremely high resolution and can separate proteins that differ by as little as a single charge.
Hoping this will be helpful,
Rafik
- Badges
- Science topic
- Similar topics
- Biological Science
- Biochemistry
- Biochemical Techniques
- Analytical Chemistry
- pH