Final answer:
SDS PAGE separates proteins based on molecular mass after they are denatured by SDS, enabling the analysis of protein purity, presence, and molecular weight in a recombinant protein sample.
Step-by-step explanation:
SDS PAGE, or Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis, is a technique commonly used in biochemistry, genetics, and molecular biology to separate proteins based on their molecular mass. During SDS PAGE, proteins are denatured by SDS, which is a detergent that binds to proteins and gives them a uniform negative charge, thereby masking their native charges. This uniformity allows the proteins to be separated in a polyacrylamide gel solely on the basis of molecular mass when an electric current is applied.
When evaluating a recombinant protein sample, SDS PAGE can provide valuable information. It can show us the presence and purity of the protein of interest, as well as its approximate molecular weight compared to a known standard molecular weight marker. The proteins are visualized as distinct bands on the gel after being stained, generally with Coomassie Brilliant Blue or a similar stain, with the distance of migration inversely related to the size of the protein.
For instance, Figure 1 from a referenced study shows the protein profiles for different biological samples, indicating the separation power of SDS PAGE in visualizing protein samples extracted from pollen and pistil of maize. Anomalies or unique patterns observed, like shifts in band size or intensity, can suggest variations in protein expression or post-translational modifications as well.