The most widely used method for determining the purity of a protein is?: (A) Isoelectric focusing, (B) Polyacrylamide gel electrophoresis, (C) Ion exchange chromatography, (D) High pressure chromatography
Answer is B. The most widely used method for determining the purity of a protein is polyacrylamide gel electrophoresis (PAGE) in the presence of an anionic detergent, sodium dodecyl sulphate (SDS). Electrophoresis separates the charged biomolecules based on the rates at which they migrate in an electrical field. Reference: Harpers illustrated biochemistry 30th edition