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4 years ago in Biochemistry , Chemistry By Raghav V

How does SDS bind to proteins and impart a negative charge during SDS-PAGE?

As a biochemist refining protocols for protein separation, I'm revisiting the foundational principles of SDS-PAGE. My experimental outcomes hinge on a precise understanding of this denaturation and charge-imparting process, not just the textbook summary. I want to ensure my interpretation of gel data is rooted in a solid mechanistic model.

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By Sonam Bhatia Answered 4 years ago

In my lab work, SDS-PAGE is a daily tool, so understanding this mechanism is crucial. I’ve seen how sodium dodecyl sulfate (SDS) works through a two-step process. First, its hydrophobic tail buries itself into the protein's core, disrupting its 3D structure and causing denaturation. Second, the negatively charged sulfate head groups coat the now-linear polypeptide chain. This essentially "swamps" the protein's intrinsic charge, creating a uniform negative charge that’s proportional to its length. This is why separation by molecular weight works so reliably.

   

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