Gel Electrophoresis

Gel Electrophoresis

• Nucleic acids, proteins, and biomacromolecules are separated and analyzed using gel electrophoresis.
• The property of nucleic acid molecules that allows them to be separated by gel electrophoresis is their charge-to-mass ratio.

Protein Separation

• Proteins are separated based on their molecular weight and charge in gel electrophoresis.

Gel Types

• Polyacrylamide gel is typically used for proteins and has high resolving power for small fragments of DNA (50-20,000 bp in size).
• Agarose gel is typically used for DNA fragments of usually 50-20,000 bp in size.

Tropomyosin Migration

• Tropomyosin's abnormal migration on SDS-PAGE gels is due to its high charge density.

Electrophoresis Basics

• The main purpose of the electric field in electrophoresis is to separate molecules based on their charge and size.
• The gel in electrophoresis acts as a sieve, slowing down the migration of larger molecules.
• The distance traveled by a band is inversely proportional to the size of the molecule in electrophoresis.

Electrophoresis Theory

• Electrophoresis is based on the principles of electrokinetic phenomenon.
• The main basis for analytical techniques used in chemistry for separating molecules is based on size, charge, or binding affinity.

Smoluchowski Theory

• According to Smoluchowski's theory of electrophoresis, the electrophoretic mobility of a dispersed particle is defined as its velocity per unit electric field strength.
• The Smoluchowski theory is limited to thin double layers, where the particle radius is much greater than the Debye length.
• The Debye length is a measure of the thickness of the electric double layer surrounding a charged particle in a colloidal suspension.
• The Smoluchowski theory neglects the contributions from surface conductivity and relaxation effects.