1) An ampholytic substance 
(from the article `separation and purification`) ...negative charges and will therefore not migrate in an electric field. This pH value is called the isoelectric point. A slab gel (or column) can be ...
a substance that may act as either an acid or a base
<chemistry> Substance with amphoteric properties. most commonly encountered as descriptive of the substances used in setting up electrofocussing columns or gels. ... (05 Feb 1998) ... 
Substance with amphoteric properties. Most commonly encountered as descriptive of the substances used in setting up electrofocusing columns or gels.
Type: Term Pronunciation: am′fō-līt Synonyms: amphoteric electrolyte
ampholyte A substance whose molecules bear both positive and negative charges.
an ampholytic substance.