EVALUATION OF THE INTERACTION OF PROTEIN ALPHA-AMINO GROUPS WITH M(II) BY IMMOBILIZED METAL-ION AFFINITY-CHROMATOGRAPHY

The adsorption properties of various peptides and proteins, lacking histidyl groups, on immobilized Cu(II), Ni(II), Zn(II) and Co(II) ions are described; at pH 6 and below they were little retarded. At higher pH the retention became pronounced for iminodiacetate (IDA)-Cu(II) gel. This effect seems to be related to the presence of a terminal-alpha-amino group; in the absence of this group the retention of the protein was largely eliminated. At pH 8.5 a terminal-alpha-amino group is adsorbed as strongly as a histidyl group. IDA-Ni(II), IDA-Zn(H) and IDA-Co(II) gels display little or no attraction for the terminal-alpha-amino group of a protein.