Practice question

Native proteins maintain folding through hydrogen bonds, ionic and hydrophobic interactions that define secondary and tertiary structure crucial for biological activity. Binding of anionic SDS along with heating with reducing agents disrupts all non-covalent forces, abolishing alpha-helices, beta-sheets and compact domains. Polypeptides convert to extended rod-like structures surrounded by negatively charged detergent micelles with random coil characteristics. Biological function and folded architecture are lost, allowing all proteins to adopt similar shape and charge density. There is no increase in molecular weight or staining enhancement; structural loss underlies uniform sieving behavior in SDS-PAGE.