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Polyacrylamide Gel Electrophoresis (PAGE) is a versatile and powerful technique used to separate and analyse biomolecules, primarily proteins and nucleic acids, based on their size and charge. PAGE is widely employed in various fields of research, including biochemistry, molecular biology, genetics, and biotechnology, for applications ranging from protein characterization to DNA sequencing.

 

The basic principle of PAGE involves the migration of charged biomolecules through a porous matrix of polyacrylamide gel under the influence of an electric field. The polyacrylamide gel matrix provides a sieving effect, allowing smaller molecules to migrate more rapidly through the gel than larger molecules. The rate of migration is influenced by both the size and charge of the biomolecules, with smaller and negatively charged molecules migrating faster than larger or positively charged ones.

 

PAGE can be performed in two main formats: denaturing PAGE and native PAGE. In denaturing PAGE, the gel matrix contains a denaturing agent such as sodium dodecyl sulfate (SDS) for proteins or urea for nucleic acids, which disrupts the native structure of the biomolecules and allows them to migrate based solely on size. Denaturing PAGE is commonly used for protein separation and analysis, such as determining molecular weight or purity of protein samples.

 

In contrast, native PAGE is performed without denaturing agents, allowing biomolecules to maintain their native conformation and charge. Native PAGE is often used for the separation of nucleic acids, particularly DNA fragments or RNA molecules, based on their size and secondary structure. It is also utilized for studying protein-protein interactions, protein-ligand binding, and enzyme-substrate interactions under native conditions.

 

Following electrophoresis, biomolecules separated by PAGE can be visualized and analyzed using various staining methods, such as Coomassie Brilliant Blue for proteins or ethidium bromide for nucleic acids. Additionally, PAGE-separated biomolecules can be further characterized or purified for downstream applications, including Western blotting, Southern blotting, or protein identification by mass spectrometry.

 

Overall, Polyacrylamide Gel Electrophoresis (PAGE) is a fundamental and indispensable tool in biological research, offering high resolution, versatility, and reproducibility for the separation and analysis of proteins and nucleic acids. Its widespread applications continue to advance our understanding of cellular processes, disease mechanisms, and molecular interactions, contributing to various fields of biomedical and life sciences.