The Western blot is a laboratory technique used to detect specific proteins in a sample. It involves separating proteins by size using gel electrophoresis, transferring them to a membrane, and then probing the membrane with antibodies that bind to the target protein. This allows researchers to identify and quantify proteins of interest. After the antibodies bind, a detection system reveals the presence of the proteins, often using a colorimetric or chemiluminescent method. Western blotting is widely used in molecular biology and biochemistry for studying protein expression, post-translational modifications, and disease markers.