Can SDS-PAGE determine protein molecular weight?

Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) is a reliable method for determining the molecular weight (MW) of an unknown protein. The first step in MW determination of a protein is to separate the protein sample on the same gel with a set of MW standards.

How do you find the molecular weight of an unknown protein in SDS-PAGE?

Use a graphing program, plot the log (MW) as a function of Rf. Generate the equation y = mx + b, and solve for y to determine the MW of the unknown protein. Run the standards and samples on an SDS-PAGE gel. Process the gel with the desired stain and then destain to visualize the protein bands.

How are proteins detected in the SDS-PAGE method?

At the end of the electrophoretic separation, all proteins are sorted by size and can then be analyzed by other methods, e. g. protein staining such as Coomassie staining (most common and easy to use), silver staining (highest sensitivity), stains all staining, Amido black 10B staining, Fast green FCF staining.

What does KDa mean in SDS-PAGE?

molecular mass
Most macromolecules are large enough to use the kiloDalton (kDa) to describe molecular mass. Molecular weight is not the same as molecular mass. It is also known as relative molecular mass (symbol Mr, where r is a subscript).

How is KDa calculated in SDS-PAGE?

Based on the values obtained for the bands in the standard, the logarithm of the molecular weight of an SDS-denatured polypeptide and its relative migration distance (Rf) is plotted into a graph. So the inverse log is 10^1.3305= 21.4kDa for the molecular weight of the unknown protein.

How do you calculate KDa for protein?

Using the equation for the linear plot we can calculate the Log (MW). (-2.0742 x 0.7084) +2.8 = 1.3305. So the inverse log is 10^1.3305= 21.4kDa for the molecular weight of the unknown protein.