What is the main purpose of elution in affinity chromatography?

The primary purpose of elution in affinity chromatography is to recover the bound protein—in this case, the Green Fluorescent Protein (GFP)—from the affinity matrix. During the affinity chromatography process, GFP is selectively attached to a column based on its specific interactions with an immobilized ligand. Once the unbound impurities are washed away, elution is necessary to disrupt this interaction and release the bound GFP into a solution.

This is typically achieved by introducing a buffer or a solution with a higher concentration of a specific molecule that competes for binding or changes the conditions (such as pH or ionic strength) to weaken the interactions between the GFP and the ligand. By effectively eluting the bound protein, researchers can collect a purified form of GFP for further analysis or application.