A polyhistidine-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.The total number of histidine residues may vary in the tag from as low as two, to as high as 10 or more His residues. Histidine （His）-tag is widely used for affinity purification of recombinant proteins, but the yield and purity of expressed proteins are quite different. This kit is developed for rapid and high throughput detection of His-tagged proteins.?