SDS-PAGE (Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis) is a widely used technique for separating proteins based on their molecular weight. Proteins are first denatured and coated with the anionic detergent SDS, which gives them a uniform negative charge. When an electric field is applied, proteins migrate through a polyacrylamide gel matrix, with smaller proteins moving faster than larger ones. SDS-PAGE is essential in protein analysis, allowing researchers to determine protein size, purity, and subunit composition.