This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
Which of the following is used to study protein-protein interaction? 
Select and explain. 
A. Western blot, B. Affinity electrophoresis, C. Thin-layer chromatography, D. None
B: Affinity electrophoresis
Answer: B: Affinity electrophoresis 
Explanation: Affinity electrophoresis is a general name for many analytical methods used in biochemistry and biotechnology. Both qualitative and quantitative information may be obtained through affinity electrophoresis. The methods include the so-called mobility shift electrophoresis, charge shift electrophoresis and affinity capillary electrophoresis. The methods are based on changes in the electrophoretic pattern of molecules (mainly macromolecules) through biospecific interaction or complex formation. The interaction or binding of a molecule, charged or uncharged, will normally change the electrophoretic propeies of a molecule. Ref-D.M.Vasudevan 7/e p659,660