Laemmli's (SDS-Sample) Buffer is widely used in molecular biology and biochemistry for preparing protein samples for SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). Its primary application is to denature proteins, ensuring they unfold and adopt a linear structure, which is essential for accurate separation based on molecular weight. The buffer contains SDS, which binds to proteins and imparts a uniform negative charge, allowing them to migrate consistently in an electric field. Additionally, it includes a reducing agent, typically beta-mercaptoethanol or dithiothreitol, which breaks disulfide bonds, further aiding in protein denaturation. Laemmli's Buffer also contains glycerol, which helps samples sink into the wells of the gel, and a tracking dye, such as bromophenol blue, to monitor the progress of electrophoresis. This buffer is a critical component in protein analysis, enabling researchers to study protein size, purity, and expression levels effectively.