Polyacrylamide gel electrophoresis (PAGE) is a technique widely used in biochemistry, molecular biology and biotechnology. It is a technique that is used to separate biological molecules such as proteins and nucleic acids, based on their shape, size, mass and charge.
Polyacrylamide is a polymer that forms soft gels upon interlinking. It is advantageous to agarose because it forms a gel with consistent pore size, and also has a higher resolving power. Sodium-dodecyl sulfate (SDS) PAGE and Native PAGE are two types of gel techniques where denature and non-denatured gels, respectively, are used for separation.
SDS PAGE
Sodium-dodecyl sulfate polyacrylamide gel electrophoresis is a technique used to separate protein molecules of masses 5 to 250 kDa. The proteins are separated solely on the basis of their molecular weight.
Sodium dodecyl sulfate, an anionic surfactant, is added in the preparation of gels that masks the intrinsic charges of the protein samples and gives them a similar charge to mass ratio. In simple words, it denatures the proteins and gives them a negative charge.
Refer: Principle of SDS PAGE
Native PAGE
Native PAGE is a technique that uses non-denatured gels for the separation of proteins. Unlike SDS PAGE, no denaturing agent is added in the preparation of gels. As a result, the separation of proteins takes place on the basis of charge and size of the proteins.
In this technique, the conformation, folding and amino acid chains of the proteins are the factors that the separation is dependent upon. The proteins are not damaged in this process, and can be recovered after the completion of separation.
SDS PAGE vs Native PAGE
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SDS PAGE |
Native PAGE |
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Description |
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SDS PAGE is a separation technique that separates proteins on the basis of their mass. |
Native PAGE is an electrophoretic technique that separates proteins on the basis of their size and charge. |
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Nature of Gel |
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The gel is denatured. |
The gel is not denatured. |
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Denaturation |
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SDS is added to the gel to impart a negative charge on the protein samples. |
No such activity is required. |
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Basis of Separation |
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The proteins are separated on the basis of mass. |
The proteins are separated on the basis of size and charge. |
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Protein Stability and Recovery |
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The proteins are not stable in the SDS PAGE, and hence cannot be recovered. |
The proteins are stable in a Native PAGE, and can be recovered later. |
Explore BYJU’S Biology to learn more.
Also Read:
- What is the difference between electrophoresis and electrolysis?
- How is Agarose gel electrophoresis done?
- What Is The Application Of Gel Electrophoresis?
Frequently Asked Questions
Is SDS used in native PAGE?
No, SDS is not used in native PAGE.
What is the purpose of SDS in SDS-PAGE?
SDS is an anionic detergent that denatures the proteins and coats them with negative charges.
Why is beta mercaptoethanol used in SDS-PAGE?
Beta-mercaptoethanol is used in SDS PAGE to reduce disulfide linkages between the proteins for easy separation.
Why is glycerol used in SDS-PAGE?
Glycerol is added to the samples to maintain their density, so that they do not diffuse out of the gel.
What are the applications of native PAGE?
Native PAGE is used for
- Characterization of soluble protein complexes, and
- Isolation of protein complexes from biological membranes.
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