Page 275 - Applied Pharmacognosy

Types of Chemical markers

 Proteins are separated according to their electrophoretic
mobility [length of polypeptide chain and its charge].

 SDS is added to the sample as well as to the gel.
 SDS being an anionic detergent denatures secondary and

tertiary protein structures, and confers a negative charge to
each denatured protein.
 On applying electric field across the gel, the negatively
charged proteins migrate towards the (+) electrode.

Ogston model for macromolecule
separation