The Basics of SDS - PAGE

"Polyacrylamide gels are formed by the reaction of acrylamide and bis-acrylamide (N,N’-methylenebisacrylamide) that results in highly cross-linked gel matrix. The gel acts as a sieve through which the proteins move in response to the electric field. Proteins contain an overall positive or negative charge; this enables the movement of a protein molecule towards the isoelectric point at which the molecule has no net charge. By denaturing the proteins and giving them a uniform negative charge, it is possible to separate them based on the size as they migrate towards the positive electrode".


SDS-PAGE of protein samples and color burst protein marker


One aspect I truly liked about learning this technique was seeing how SDS and PAGE both combined to  use one characteristic, molecular size. The two other physical properties that are dismissed are the charge and structure due to detergents SDS amphipathic nature.

https://www.sigmaaldrich.com/US/en/technical-documents/protocol/protein-biology/gel-electrophoresis/sds-page

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