His-Tag Protein Purification is a series of processes intended to isolate target protein from a complex mixture. A His-Tag is an amino acid motif in proteins that typically consists of at least six histidine (His) residues, often at the N- or C-terminus of the protein. Several metal cations have high affinities for imidazole, the function group of His-Tag. Transition metal imidazole complexes are well known for M2+ (M = Mn, Fe, Co, Ni, Cu). Nickel is a widely used metal ion in the purification of His-Tag protein. https://www.ste-mart.com/h...