By adding SDS during protein electrophoresis, it is possible to: to. Preserve the native structure and biological activity of a protein. B. Separate proteins solely on the basis of molecular weight. C. Determine the amino acid composition of the protein D. Determining the isoelectric point of a protein By adding SDS during protein electrophoresis, it is possible to: to. Preserve the native structure and biological activity of a protein. B. Separate proteins solely on the basis of molecular weight. C. Determine the amino acid composition of the protein D. Determining the isoelectric point of a protein.