ampholyte

An ampholyte is a molecule that can act as either an acid or a base, a property known as being amphoteric. Amino acids are a prime example of ampholytes because they possess both a basic amino group and an acidic carboxyl group.1

At physiological pH (around 7-7.4), amino acids exist as zwitterions, which are ions carrying an equal number of positive and negative charges. The specific pH at which a molecule has a net zero charge is called the isoelectric point (pI). This amphoteric nature is crucial in understanding the biochemistry of amino acids and proteins. Ampholytes are also used in a technique called isoelectric focusing (IEF) to separate proteins based on their unique isoelectric points.12