9713286 Ataai Purification of a target protein constitutes the major fraction of the total cost of its production. The high cost of purification often limits the availability of such proteins, which in turn impedes studies in immunology, vaccine development, and the production of pharmaceutical and diagnostic reagents for human health care. Although immunoaffinity purification should allow for purification of such target proteins, it suffers from a number of shortcomings including high cost of the ligand, and, in some cases, strong binding of the target protein to the antibody, which could require the use of extremes of pH or other harsh conditions for the elution of the protein. IMAC has shown promise for the purification of proteins fused to metal affinity tails. Based on preliminary results, screening of combinatorial peptide libraries may identify peptides capable of purifying target fusion proteins in one chromatography step with high recovery, purity, and low cost. ***