Isoelectric focusing (IEF), also known as electrofocusing, is a technique for separating different molecules by their electric charge differences. It is a type of zone electrophoresis, usually performed in a gel, that takes advantage of the fact that a molecule's charge changes with the pH of its surroundings. A protein which is in a pH region below its pI will be positively charged and so will migrate towards the cathode. However, as it migrates, the charge will decrease until the protein reach… (More on Electrofocusing)