In this protocol, what is the primary purpose of using hydrophobic interaction chromatography?

In this protocol, what is the primary purpose of using hydrophobic interaction chromatography?

• A. To separate proteins based on hydrophobicity.
• B. To separate by charge.
• C. To separate by size.
• D. To separate by affinity to a ligand.

Answer: (A)

Hydrophobic interaction chromatography works by separating proteins based on how hydrophobic their surfaces are. In a high-salt environment, hydrophobic patches on a protein interact strongly with the hydrophobic ligands on the resin, so more hydrophobic proteins bind more tightly. To elute the bound proteins, the salt concentration is gradually lowered (or the solvent polarity is increased), weakening those hydrophobic interactions; proteins with weaker hydrophobicity come off first, while more hydrophobic proteins stay bound longer and elute later. This makes the method particularly useful for distinguishing proteins that are similar in charge and size but differ in surface hydrophobicity. Other chromatography types separate primarily by charge (ion exchange), size (size-exclusion), or specific ligand binding (affinity), rather than by hydrophobicity.

Hydrophobic interaction chromatography works by separating proteins based on how hydrophobic their surfaces are. In a high-salt environment, hydrophobic patches on a protein interact strongly with the hydrophobic ligands on the resin, so more hydrophobic proteins bind more tightly. To elute the bound proteins, the salt concentration is gradually lowered (or the solvent polarity is increased), weakening those hydrophobic interactions; proteins with weaker hydrophobicity come off first, while more hydrophobic proteins stay bound longer and elute later. This makes the method particularly useful for distinguishing proteins that are similar in charge and size but differ in surface hydrophobicity. Other chromatography types separate primarily by charge (ion exchange), size (size-exclusion), or specific ligand binding (affinity), rather than by hydrophobicity.