Isoelectric Focusing Electrophoresis

Isoelectric focusing (IEF) electrophoresis, also known as electrofocusing electrophoresis, is a molecular technique used in labs for the separation and analysis of proteins and peptides based on the difference in their isoelectric point (pI) by the application of an electric field along a pH gradient formed in a capillary. It is a type of zone electrophoresis usually performed on proteins in a gel that takes advantage of the fact that overall charge on the molecule of interest is a function of the pH of its surroundings. The technique is especially useful to separate proteins of the same molecular weight.