Size Exclusion Chromatography v1

Size-exclusion chromatography (SEC) is a method for separating proteins according to their size. To achieve this, a protein sample is applied to a column that is tightly packed with porous beads.The size separation is determined by the thickness of the hydration shell of the proteins in a solvent. Small molecules can penetrate the pores, while large molecules cannot and are eluted first from the column. Smaller proteins follow, whereby the elution time is inversely proportional to the protein size. We used this method to investigate whether proteins form a stable complex. The individual complex partners have a characteristic elution profile. If there is a stable interaction, they are expected to co-elute after mixing.