Electrophoresis

From ArticleWorld

Electrophoresis is the movement of a charged substance under the influence of an electric field. This movement is attributed to a force referred to as the Loentz force. Electrophoresis is a major technique used today in the separation of molecular substances. It is of great value to cell biology and molecular biology. Regardless of the many layouts of the equipment used all of these operate on the same principle of allowing molecules to migrate based on the charge distribution of the molecules in question.

Basics

This method of separation can be employed as a one dimensional or two dimensional plane of separation. One dimentional has applications to protein and nucleic acid separations but two dimensional separations most used in proteins used for fingerprinting which can provide accurate resolution of all the proteins in the cell. The medium used in this method is usually a gel or it can be layered into flat sheets. The sheets are most used for two dimensional separations while the tubes are used for one dimensional separations.

Cationic vs. anionic systems

Proteins are separted based on their charge in electrophoresis. This charge may be either negative or positive depending on the pH of the buffer. In the separation, a column of gel is usually used which is separated into three sections. Electrodes are attached to the column and an electric charge is passed through the system. The arrangement of the system is important here in determining cationic or anionic systems. If the bath is cationic then the positive cations flow to the cathode. If the arrangement is that the upper bath is the negative cathode while the lower bath is the positive anode then the negative anions flow to the positive anion and this is the anionic system.