What type of proteins might appear larger than they are in size exclusion chromatography?

Proteins with elongated structures can appear larger than their actual size in size exclusion chromatography (SEC) due to their shape affecting how they interact with the porous gel medium used in the chromatography process. Size exclusion chromatography separates molecules based on their size, with larger molecules typically eluting faster because they cannot enter the pores of the gel as easily as smaller molecules.

However, proteins that are elongated or have a rod-like shape can effectively "fit" into the pores in a way that gives them a larger hydrodynamic volume compared to their actual molecular weight. In essence, these proteins might take longer to elute than one would expect based solely on their molecular weight because their distinct shape influences their passage through the porous matrix. As a result, it is the combination of size and shape that leads to a misinterpretation of size in SEC, making elongated proteins appear larger than they truly are in terms of molecular weight.