isoelectric point

noun

: the point or narrow range on a pH scale at which an amphoteric molecule or surface carries no electrical charge, or in which the negative and positive charges are equal resulting in a net zero charge : the pH at which an amphoteric molecule will not migrate in an electrical field

Proteins migrate to the pH region corresponding to their isoelectric point, where they become immobilized because of a zero net charge.

—David R. Burwasser, Technical Survey

Pyrogenic exotoxin C is characterized by an isoelectric point of 7.2 …

—Steven E. Schutzer et al., Science

see isoelectric focusing