mouse monoclonal IgG1; His-Tag Antibody (H-3) is an IgG1 κ mouse monoclonal His-Tag antibody (also designated 6X His-Tag antibody or His-Probe antibody) that detects the His-Tag protein. His-Tag Antibody (H-3) is available as both the non-conjugated anti-His-Tag antibody form, as well as multiple conjugated forms of anti-His-Tag antibody, including agarose, HRP, PE, FITC and multiple Alexa Fluor® conjugates. Plasmid vectors for the expression of coding regions of eukaryotic genes in bacterial, insect and mammalian hosts are in common usage; such expression vectors are frequently used to encode hybrid fusion proteins consisting of a eukaryotic target protein and a specialized region designed to aid in the purification and visualization of the target protein. A system that has proven to be very successful relies on the insertion of a six histidine (His6) sequence in the N-terminus of the encoded protein, allowing for efficient coupling to Ni2+-chelating resins and purification by single step affinity chromatography. This polyhistidine sequence can then be removed by specific cleavage at sites recognized by enzymes such as thrombin or enterokinase, permitting the separation of the target protein from the polyhistidine tag. Visualization of such fusion proteins can be achieved by utilizing antibodies generated against specific peptide sequences downstream from the multiple cloning site.