SDS Polyacrylamide Gel Electrophoresis: Separating Proteins by Molecular Weight

The Purpose of SDS Polyacrylamide Gel Electrophoresis

SDS polyacrylamide gel electrophoresis is a technique used to separate proteins based on their molecular weight. It accomplishes this by denaturing proteins to their linear form and masking their native charges, hence allowing separation solely based on size.

How Does SDS-PAGE Work?

Among the given statements about SDS polyacrylamide gel electrophoresis, the correct one is: SDS polyacrylamide gel electrophoresis separates proteins on the basis of their molecular weight. SDS (Sodium Dodecyl Sulfate) polyacrylamide gel electrophoresis (PAGE) is a widely used method for separating proteins based on their molecular weight. SDS reduces proteins to their denatured, linear form so that separation occurs solely based on size, rather than shape or charge. This is achieved due to the unique properties of SDS, which is a detergent that denatures proteins and masks their native charges, making them uniformly negatively charged.

Thus, separation and visualization of proteins using SDS-PAGE are based on their relative molecular masses, with smaller proteins moving faster through the gel matrix and being separated further down the gel. It is crucial to note though, that after SDS polyacrylamide gel electrophoresis, proteins are denatured and hence, cannot be tested for their biological activity afterwards.