What is one purpose of using SDS in SDS-PAGE?

In the context of SDS-PAGE (Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis), one of the primary purposes of using SDS is to denature proteins. SDS is an anionic detergent that binds to proteins and disrupts their native structures. This denaturation process unfolds the proteins and imparts a negative charge proportional to their mass, allowing them to move through the polyacrylamide gel when an electric field is applied.

As each protein becomes uniformly coated with SDS, their intrinsic charges and structures are eliminated, leading to separation based primarily on size rather than shape or charge. This is essential for effective electrophoresis because it ensures that proteins with similar molecular weights can be compared directly as they migrate through the gel, resulting in clear bands that represent different proteins.

In contrast, while other options also discuss aspects related to protein handling, they do not accurately capture the fundamental role of SDS in the denaturation process that is crucial for the separation of proteins by size in SDS-PAGE.