<prompt> Which of the following is used to study protein-protein interaction ?Western blotAffinity electrophoresisThin-layer chromatographyNone  <response>: Ans. is b i.e., Affinity electrophoresis The most conventional and widely used high-through put methods for protein-protein interactions PPI are yeast two-hybrid screening and affinity purification coupled to mass spectroscopy. Other methods used to study PPI are :- LI Affinity electrophoresis Co-immunoprecipitation Protein microarrays Analytical ultracentrifugation Light scattering Fluorescence spectroscopy SPINE strep-protein interaction experiment LUMIER luminescence-based mammalian intractome mapping Calorimetry QUICK quantitative immunoprecipitation combined with knock-down BiFC Biomolecular fluorescence complementation PLA Proximity ligation assay Resonance energy transfer system Mammalian protein-protein interaction trap Surface plasma resonance Protein-fragment complementation assay Tandom affinity purification 