Which statement about SDS-PAGE is correct?

SDS-PAGE, or sodium dodecyl sulfate polyacrylamide gel electrophoresis, is a technique primarily used to separate proteins based on their molecular weight. The correct statement about SDS-PAGE is that it requires a denaturing gel. During the process, sodium dodecyl sulfate (SDS) is used to denature proteins, which unfolds them and imparts a negative charge proportional to their length. As a result, when an electric field is applied, the proteins move through the gel matrix towards the positive electrode.

The denaturing aspect is crucial because it ensures that the separation is based solely on the size of the proteins; the SDS coats the proteins and negates their intrinsic charge, allowing them to migrate according to their molecular weight rather than charge-related properties. This makes SDS-PAGE highly effective for analyzing complex protein mixtures.

Other options do present misleading premises about how SDS-PAGE functions, particularly regarding the separation mechanism and visualization of proteins, making it important to discern the specific role of denaturation in the process.