Purification of serum amyloid A and other high density apolipoproteins by hydrophobic interaction chromatography

A chromatographic procedure is described for the purification of apolipoprotein components of high density lipoprotein from serum. Hydrophobic interaction chromatography (HIC) using phenyl- or octyl-Sepharose was used to purify the high density lipoprotein (HDL)-associated acute phase reactant serum amyloid A (SAA). The purification of SAA is described in detail and it is shown how the main components of normal HDL, apolipoproteins AI and AII (Apo-AI, Apo-AII), can also be purified. Serum was applied at a low salt concentration and apolipoproteins were eluted with a gradient into 4 M guanidine hydrochloride, 30% ethanediol, and 10 mM NaOH. This method was also used to partially purify the low density lipoprotein component apolipoprotein B. Apolipoproteins are purified free from lipid in one rapid chromatographic procedure rather than several ultracentrifugation steps and delipidation with organic solvents. The apolipoproteins from HIC chromatography are already partially separated and can be purified to homogeneity using conventional chromatographic methods under dissociating conditions.