Difference Between SDS Page and Native Page

Key Difference – SDS Page vs Native Page
 

SDS and native page are two types of polyacrylamide gel electrophoresis techniques used in Molecular Biology. The key difference between SDS Page and Native Page is the type of polyacrylamide gel used. In SDS Page a denaturing gel is used therefore, molecules are separated based on their molecular weight. In contrast, in Native Page, non-denaturing gels are used. Therefore, molecules are separated based on their size, charge and shape.

Polyacrylamide Gel Electrophoresis (Page) uses a gel made by polymerizing acrylamide monomers with methylene bisacrylamide. The polyacrylamide is tougher and more heat stable than agarose. The polyacrylamide gels have a smaller pore size that enables the efficient separation of proteins. There are two main types of Page setups namely SDS Page and Native Page. SDS Page or Sodium-Dodecyl Sulfate Polyacrylamide gel electrophoresis separates proteins based on their molecular weights. Denaturing gels are used in SDS Page. Native Page uses non-denaturing gels and separates proteins based on their size, charge and the shape (3D conformation).

CONTENTS

1. Overview and Key Difference
2. What is SDS Page
3. What is Native Page
4. Similarities Between SDS Page and Native Page
5. Side by Side Comparison – SDS Page vs Native Page in Tabular Form
6. Summary

What is SDS Page?

SDS Page is the most common electrophoretic technique used to separate proteins based on their molecular weight. The gel is made by adding SDS (Sodium dodecyl sulfate), which is a detergent. SDS dentures proteins into monomers. SDS is an anionic detergent. Therefore, it adds a net negative charge to the proteins within a wide pH range. When the net negative charge is imparted on the protein molecules, due to the charge variation, the complex structures are broken down. Due to the negative charge, proteins attract towards the positive end. Thus molecules with lower molecular weight travel faster on the gel matrix and can be observed close to the anode, whereas the higher molecular weight proteins are observed closer to the wells.

The SDS binding to the polypeptide chain is proportional to its relative molecular mass. Therefore, the molecular mass can also be determined via SDS Page. The staining of the SDS Page gels is done by bromophenol blue staining. Applications of SDS page range to a larger extent where it can be used to estimate the relative molecular mass and to determine the relative abundance of proteins in a protein mixture. SDS Page can also be used to determine the protein distribution in a mixture of proteins. SDS Page is also applied to purify and assessing proteins. It is used as a preliminary procedure for western blotting and hybridization, which in turn is used for protein mapping and identification.

What is Native Page?

Native Polyacrylamide gel electrophoresis (Native Page) uses a non – denaturing gel. Therefore, SDS or any other denaturing agent is not added to the gel matrix. In Native Page, the separation of proteins is based on the charge and the size of the protein. Therefore, the mobility of the protein depends on the charge and the size of the protein.

The charge of the protein depends on the side chains of the amino acids. If the side chains are negatively charged, the protein will receive an overall negative charge and vice versa. Proteins retain a 3D conformation due to the folding that takes place. Folding results from the several bond types in proteins such as disulfide bonds, hydrophobic interactions and Hydrogen bonds. Therefore, if the native Page is carried at a neutral pH, the proteins will be separated according to the molecular shape of the protein. Therefore, Native Page can be used as a sensitive technique to detect the change in charge or conformation of the protein.

The main advantage of native Page is that the protein used for the Page analysis can be recovered in its original state after the Page analysis, as the protein is not disturbed during the process. Native Page is a relatively high throughput technique, and the stability of the protein is increased.

Upon completion of the gel run, the Native Page gel can be viewed by staining with bromophenol blue or any other suitable staining reagent. The applications of Native Page includes separation of acidic proteins including glycoproteins such as human recombinant erythropoietin or the identification of proteins present in Bovine Serum Albumin (BSA).

What are the Similarities Between SDS Page and Native Page?

• Both SDS Page and Native Page systems use polyacrylamide gel as the matrix of the gel.
• Both are used for separation and identification of proteins.
• Both use electrophoretic mobility to separate the compounds.
• Both can be done in a vertical manner or horizontal manner (mostly done as vertical Page setups because the run length is more).
• The electrophoresis apparatus including the gel tank, combs, the power supply is required for the operation of both techniques.
• The visualizing of the gel can be done by staining methods in both techniques.

What is the Difference Between SDS Page and Native Page?

Summary – SDS Page vs Native Page

SDS Page and Native Page are two types of Polyacrylamide gel electrophoresis techniques used to separate proteins. SDS Page is treated with a detergent called SDS. SDS imparts an overall negative charge to the protein, which then results in the denaturation of the protein. Therefore, the proteins are separated based on their molecular weight. In contrast, the Native Page technique does not use any denaturing agent. Thus the proteins are either separated based on their size or the shape. This is the difference between SDS page and native page.

Reference:

1.“The Principle and Method of Polyacrylamide Gel Electrophoresis (SDS-PAGE).” The Principle and Method of Polyacrylamide Gel Electrophoresis (SDS-PAGE) | MBL Life Sience -ASIA-. Available here
2.“Native Gels.” Alliance Protein Laboratories|Biophysical Characterization Services. Available here  

Image Courtesy:

1.’SDS-PAGE Electrophoresis’By Bensaccount at English Wikipedia, (CC BY 3.0) via Commons Wikimedia  
2.’Load a sample into a polyacrylamide gel electrophoresis well’By Blaz Nemec from Ljubljana, Slovenia (CC BY-SA 2.0) via Commons Wikimedia