Structural Biochemistry/Proteins/Purification/Hydrophobic Interaction Chromatography
Hydrophobic Interaction Chromatography (HIC) (or Hydrophobic Chromatography) is a method of separation by using salt gradients (i.e. ammonium sulfate) to generate hydrophobic interactionsbetween protein and the ligands on the solid phase support resin . The purpose of this type of chromatography is to utilize the hydrophobic properties of specific proteins rather than their charges, which is used in ion-exchange chromatography. Therefore, the more hydrophobic a protein is, stronger it will cling to the column and elution proceeds with the least hydrophobic proteins emerging first from the column. The salt gradient is important because it increases hydrophobic interaction and stabilizes proteins . During elution, other factors besides hydrophobicity still affect how proteins separate, such as ionic interactions, pH, temperature, salt concentration, solvent amount, buffer conditions, etc. These attributes also point to the similarities between HIC and reverse phase chromatography and affinity chromatography . It is important to note that HIC is advantageous because it can be prepared for specific proteins and applied to different facets of protein purification. Conditions may be altered in minor ways to apply the test to many other situations for purification and study purposes, especially in cell membrane studies.
- Wikibook:Proteomics - Hydrophobic Interaction Chromatography 
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