In the described purification, how do high-salt binding conditions affect hydrophobic proteins in column chromatography?

In the described purification, how do high-salt binding conditions affect hydrophobic proteins in column chromatography?

• A. Hydrophobic proteins in the binding buffer bind to the beads on the column due to hydrophobic interactions in high salt.
• B. Hydrophilic proteins bind to the beads on the column.
• C. All proteins bind regardless of hydrophobicity.
• D. Hydrophobic proteins pass through the column without binding.

Answer: (A)

In this type of purification, high salt promotes binding through hydrophobic interactions. The column is packed with hydrophobic ligands, so when the salt concentration is high, proteins become less soluble and hydrophobic regions on their surfaces are more likely to interact with the hydrophobic beads. That causes hydrophobic proteins to stick to the column. As the salt concentration is lowered, those weak hydrophobic interactions weaken and the proteins elute, enabling separation. Hydrophilic proteins don’t bind strongly under these conditions, and not all proteins bind regardless of hydrophobicity. Hydrophobic proteins wouldn’t pass through without binding under high-salt conditions.

In this type of purification, high salt promotes binding through hydrophobic interactions. The column is packed with hydrophobic ligands, so when the salt concentration is high, proteins become less soluble and hydrophobic regions on their surfaces are more likely to interact with the hydrophobic beads. That causes hydrophobic proteins to stick to the column. As the salt concentration is lowered, those weak hydrophobic interactions weaken and the proteins elute, enabling separation. Hydrophilic proteins don’t bind strongly under these conditions, and not all proteins bind regardless of hydrophobicity. Hydrophobic proteins wouldn’t pass through without binding under high-salt conditions.