What happens to large proteins during size exclusion chromatography?

In size exclusion chromatography, large proteins experience a specific interaction with the stationary phase within the column. The beads in the column are designed with pores that allow smaller molecules to enter, while larger proteins are generally too big to fit through these pores.

As a result, large proteins cannot penetrate the beads, which means they do not get stuck in the pores and are not retained within the column. Instead, they follow a simpler pathway around the beads, allowing them to exit the column earlier than smaller proteins, which do take more time due to their ability to enter the pores and navigate through a more complex pathway.

Thus, large proteins exit the column first because they are unable to enter the beads, making both aspects of the selected answer accurate. The understanding of protein behavior in size exclusion chromatography is essential for separating biomolecules based on their size, leading to clear distinctions in elution profiles between large and small proteins.