High-performance hydrophobic-interaction chromatography of proteins on a series of poly(alkyl aspart-amide)-silicas

Abstract

A series of bonded poly(alkyl aspartamide) coatings was prepared on silica. The products showed a wide range of hydrophobicity, and were evaluated for high-performance hydrophobic-interaction chromatography (HPHIC) of proteins. Poly-(propyl aspartamide)-silica is a good general-purpose material for protein HPHIC; poly(ethyl aspartamide)-silica may be useful for more hydrophobic proteins. Retention of proteins generally increased dramatically with ligand length in the coating, but this was not true of certain apolipoproteins with no well-defined tertiary structure. A correlation was also observed between peak width and conformational lability; the apolipoproteins (an extreme case) were eluted in exceptionally broad peaks. These principles can be used to obtain data on the physical characteristics of new proteins. This was demonstrated with rec A protein.