zwitterionilisation
Zwitterionilisation refers to the process by which a molecule containing both acidic and basic functional groups, such as an amino acid, can exist as a zwitterion. A zwitterion is a neutral molecule that has an equal number of positive and negative electrical charges distributed within its structure. This state is typically achieved in aqueous solutions at a specific pH value known as the isoelectric point (pI). At the isoelectric point, the molecule carries no net charge, and its solubility is often at its minimum.
The process of zwitterionilisation involves the internal transfer of a proton. For example, in an amino acid