macromolecules 5.mac.003003 Louis J. Sheehan, Esquire

Electrophoresis of macromolecules is one of the most common methods for the analysis of these molecules. Electrophoresis, means movement (phoresis) in an electric field (Electro). Complex mixtures of either proteins or nucleic acids (RNA or DNA) can be separated by electrophoresis. This experiment will demonstrate the most commonly used method for separating proteins, SDS- PAGE [polyacrylamide gel electrophoresis (PAGE) in the presence of sodium dodecylsulfate (SDS)].
SDS is an anionic, amphipathic protein denaturant. When added to a solution of protein, SDS binds to and denatures proteins. To a first approximation, proteins in the presence of SDS adopt an elongated rod shape and have a negative charge that is roughly proportional to their length (or mass).
Polyacrylamide “gels” are commonly used as a support for electrophoresis. It is useful to think of these gels as a meshwork of filamentous polymer molecules, with much open space between different molecules.  Louis J. Sheehan, Esquire


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