The classification and principle of gel electrophoresis are briefly described.

The classification and principle of gel electrophoresis are briefly described as follows:

Biological macromolecules, such as protein, nucleic acids and polysaccharides, have cationic and anionic groups, which are called zwitterions. Usually dispersed in solution in the form of particles, their electrostatic charge depends on the concentration of H+ in the medium or the interaction with other macromolecules. In the electric field, charged particles migrate to the cathode or anode, and the migration direction depends on their charged symbols. This migration phenomenon is called electrophoresis.

The basic principles of electrophoresis can be summarized as charge properties of charged particles, establishment of electric field, movement of charged particles, separation and analysis of charged particles.

1, the charge properties of charged particles

Substances separated by electrophoresis must have ionizable groups, such as amino group (-NH2) or carboxyl group (-COOH). These groups can ionize ions in aqueous solution, thus charging particles.

2, the establishment of electric field

In electrophoresis tube, charged particles move under the action of electric field. The two ends of the electric field are usually called electrodes. Usually, one electrode is positively charged and the other is negatively charged.

3. Moving charged particles

Under the action of electric field, positively charged particles move to the negative electrode and negatively charged particles move to the positive electrode. This movement is called electromigration.

4. Separation and separation analysis of charged particles

Under the action of electric field, the moving speed of charged particles in electrophoresis tube is related to their charge amount, shape and size. Therefore, different charged particles move at different speeds in the electric field, thus realizing separation and analysis.

Uses of electrophoresis:

1, biomolecule separation

Electrophoresis is most commonly used to separate biomolecules, such as protein, nucleic acids, enzymes and viruses. For example, polyacrylamide gel electrophoresis can use both charge effect and molecular sieve effect to separate substances with different molecular sizes and charges. This technique has high resolution and selectivity, and can detect a very small amount of samples, such as 10-9 to10-12g.

2. Physical examination

Electrophoresis technology has an important application in medical examination. For example, serum protein electrophoresis can be used to diagnose liver diseases and immune system diseases, and urine protein electrophoresis can help diagnose kidney diseases and urinary system problems. Electrophoresis can also be used for identification of bacteria, diagnosis of infectious diseases and prenatal diagnosis of genetic diseases.

3. Basic research and applied research

Electrophoresis technology is also widely used in basic research and applied research. For example, epigenetic modifications of protein, such as methylation or acetylation, can be studied by electrophoresis to understand its function in organisms. Electrophoresis can also be used to study the interaction between enzyme activity and other biomolecules, such as the interaction between DNA and protein.