The 6 X histidine motif is used as a tag on many recombinant proteins to facilitate purification.It can then be purified using immobilized metal ions,traditionally nickel,in a procedure termed immobilized-metal affinity chromatography.Further analysis of the protein can be achieved using an antibody specific to the 6 X histidine in techniques such as western blotting.The antibody recognizes the His-tag fused to targeted proteins in transfected or transformed cells.