Surfactant-mediated protein hydrophobic-interaction chromatography

Area of Science:

• Biochemistry
• Analytical Chemistry
• Protein Chemistry

Background:

• Hydrophobic-interaction chromatography (HIC) is a key protein separation technique.
• Surfactants are often used to modulate HIC but their precise interactions with proteins are complex.
• Understanding these interactions is crucial for optimizing protein purification.

Purpose of the Study:

• To investigate the effect of submicellar concentrations of CHAPS on protein retention in HIC.
• To determine if protein retention is solely dependent on surface tension.
• To propose an alternative model for surfactant-protein interactions in HIC.

Main Methods:

• Hydrophobic-interaction chromatography was performed on three model proteins: lysozyme, pancreatic trypsin inhibitor, and ribonuclease A.
• Varying concentrations of the surfactant CHAPS (below its critical micelle concentration) were used.
• Protein retention times were measured at different CHAPS concentrations.

Main Results:

• CHAPS demonstrated selectivity, increasing retention for lysozyme and pancreatic trypsin inhibitor while decreasing it for ribonuclease A.
• The dependence of retention on CHAPS concentration varied significantly among the tested proteins.
• Protein retention changes were not directly correlated with the monotonic decrease in surface tension.

Conclusions:

• Protein retention in HIC is not a simple function of surface tension when using surfactants like CHAPS.
• The observed selectivity suggests complex, protein-specific interactions with the surfactant.
• A model involving multiple equilibria and kinetic components is proposed to explain CHAPS-protein interactions and retention behavior.