What is a primary use of SDS-PAGE?

SDS-PAGE, which stands for Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis, is primarily utilized to separate proteins based on their size. This technique employs the principle that proteins, when treated with sodium dodecyl sulfate (SDS), become denatured and acquire a negative charge in proportion to their length. When an electric field is applied during electrophoresis, these negatively charged protein complexes migrate through a polyacrylamide gel matrix. Smaller proteins move through the gel more easily and quickly than larger ones, leading to separation.

This method is pivotal in biochemical laboratories for analyzing protein purity, estimating molecular weight, and identifying proteins in complex mixtures. The ability to separate proteins by size makes it an essential tool in applications such as protein characterization, verification of recombinant protein expression, and assessment of post-translational modifications.

While extracting proteins or visualizing DNA fragments are important processes in molecular biology and biochemistry, they are not the primary function of SDS-PAGE. Stabilizing cell membranes during purification does not relate directly to the objectives of SDS-PAGE either, further emphasizing that separation of proteins based on size is the method's core utility.