Preparation of magnetic immobilized metal affinity separation media and its use in the isolation of proteins

A new method of pseudobiospecific protein isolation is developed and tested, which employs both metal affinity and magnetism as the basis for isolation. The chelating group iminodiacetic acid (IDA) has been coupled to the surface of magnetic agarose, and when charged with metal ions (Cu2+ or Zn2+) is capable of binding model proteins which display metal affinity, and of separating protein mixtures. Magnetic properties of the medium facilitated the batch recovery of the adsorbent, as losses are minimized by concentrating and retaining the separation medium with the aid of a magnet. Model proteins were used to characterize protein adsorption, capacity, and stability of IDA magnetic agarose. Recovery from a cell lysate was demonstrated by protein isolation from extracts of E. coli containing a target protein. Overall, this study effectively illustrates the engineering of separation media which combine several desired properties for the development of a new branch of metal affinity-based bioseparation. (C) 1998 Elsevier Science B.V.