Ni-NTA Agarose is an affinity chromatography matrix for purifying recombinant proteins carrying a His tag. Histidine residues in the His tag bind to the vacant positions in the coordination sphere of the immobilized nickel ions with high specificity and affinity. Cleared cell lysates are loaded onto the matrices. His-tagged proteins are bound, and other proteins pass through the matrix. After washing, His-tagged proteins are eluted in buffer under native or denaturing conditions.