Host: The Society of Chemical Engineers, Japan
Investigation and utilization of peptides and proteins depend upon their separation and purification, which may be accomplished with chromatographic methods. Among the possible methods, immobilized metal affinity chromatography (IMAC), first reported by Porath, is known as a useful and powerful tool of the separation and analysis of the peptides and proteins and currently becomes the most popular chromatographic technique. A metal-affinity immobilized liposome chromatography (MA-ILC) was newly developed as a new chromatographic technique to separate and analyze the protein. The MA-ILC was prepared from the immobilized liposome modified with the functional ligands. A N-hexadodecyl -imonodiacetic acid (HIDA) was then used as the functional ligand. The metal ion Cu(II) was first adsorbed by the coordination with the functional ligand-modified liposome, immobilized on a gel matrix before the analysis of the elution behaviors. Synthetic peptides ranging in size from 5 to 40 residues were used to evaluate the retention properties of MA-ILC. The retention properties using usual imidazole elution for MA-ILC at 303 K was compared with those for IMAC, which is a most popular separation method for proteins, and an immobilized liposome chromatography (ILC), which can separate and analyze the protein mainly by the hydrophobic interaction between the liposome and protein. The retention ability of peptide on MA-ILC has both the properties of IMAC and ILC; the capacity factor depends on both the number of His residue in peptide and the hydrophobicity of peptide. It is considered that the retention properties of IMAC could be related not only to the hydrophobic interaction between the peptide and liposome but also to the cluster formation of the ligands on the liposome surface.