SDS-PAGE stands for Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis. It is a laboratory technique used to separate proteins based on their size. In this method, proteins are treated with SDS, a detergent that denatures them and gives them a negative charge. When an electric current is applied, the proteins move through a gel matrix, with smaller proteins traveling faster than larger ones. After the separation, the proteins can be visualized using various staining methods. This allows researchers to analyze protein purity, size, and quantity. SDS-PAGE is widely used in biochemistry and molecular biology for protein characterization and identification.