Polyacrylamidegelelektroforese

Polyacrylamidegelelektroforese, often abbreviated as PAGE, is a widely used analytical technique in biochemistry and molecular biology. It is a method for separating macromolecules, primarily proteins and nucleic acids, based on their size and charge. The technique utilizes a gel matrix made from polyacrylamide, which is formed by the polymerization of acrylamide and bis-acrylamide monomers. This gel acts as a molecular sieve, with smaller molecules migrating more quickly through its pores than larger ones.

In PAGE, the sample containing the macromolecules is loaded into wells at one end of the gel. An electric current is then applied across the gel. Molecules with a net negative charge will migrate towards the positive electrode (anode), while those with a net positive charge will move towards the negative electrode (cathode). The pore size of the polyacrylamide gel can be adjusted by altering the concentration of acrylamide, allowing for the separation of molecules within a specific size range.

After the electrophoresis is complete, the separated molecules are visualized using various staining techniques. For proteins, common stains include Coomassie Brilliant Blue or silver staining. For nucleic acids, ethidium bromide or other fluorescent dyes are used. The resulting pattern of bands on the gel provides information about the molecular weight and relative abundance of the components in the original sample. PAGE can be performed under native conditions, preserving the protein's native conformation, or under denaturing conditions, using agents like SDS (sodium dodecyl sulfate) to linearize proteins and separate them solely based on size. This versatility makes PAGE a powerful tool for research and diagnostics.