Practice question

Affinity chromatography exploits highly specific, reversible biological interactions such as enzyme-substrate, antibody-antigen, or receptor-ligand binding. Matrix immobilized with ligand captures target molecule while others pass through. To achieve purity, initial binding step is followed by extensive buffer wash to remove unbound contaminants, then additional wash to eliminate non-specifically adsorbed molecules via low-stringency conditions. Only after clearance does specific elution occur using competitive ligand, pH shift, or high salt to disrupt interaction. Hence complete purification sequence involves ligand binding, non-specific washing, and final desorption, ensuring high-fold enrichment of desired biomolecule from crude extracts.