Now, once we isolate the protein sample, we take the sample of proteins and place it into a gel electrophoresis setup. So we use SDS polyacrylamide gel electrophoresis and that allows us to use an electric field to separate the proteins based on their size. So this is what we get following our gel electrophoresis experiment. And so this band represents those proteins that are the largest in size. And this band represents the proteins that are the smallest in size. Remember, in SDS polyacrylamide gelatrophrases, these proteins move as a result of charge, as a result of being inside an electric field.