Penta·His Antibody, BSA-free (100 µg)

QIAGEN offers the Penta·His Antibody, BSA-free, a monoclonal mouse antibody developed for sensitive detection of His-tagged proteins. It recognises the HHHHH epitope and binds 5xHis tags located at the N-terminus, C-terminus or internally within recombinant proteins. According to the manufacturer, the antibody binds to proteins carrying 6xHis tags regardless of the surrounding amino acids, even when the tag is partially hidden.

The antibody is of the Mouse IgG1 isotype and shows negligible cross-reactivity with crude E. coli, yeast, mammalian or insect cell lysates. It is supplied in lyophilized form and is stable without BSA. Manufacturer data report a sensitivity of 0.5 ng in dot blots and 2 ng in western blots. The dissociation constant (Kd) for the HHHHH epitope has been measured at 5 x 10⁻⁸ – 1 x 10⁻⁹ M by surface plasmon resonance (BIACORE), with the exact value dependent on the individual 6xHis-tagged protein.

Prepared under serum-free conditions, the antibody is free of viruses, mycoplasma and contaminating immunoglobulins. It has been used to detect His-tagged proteins such as DHFR, Thioredoxin, TNF-α, TFIIAγ, chaperonin and DNA polymerase. It is suited to applications including identification of positive expression clones by colony blotting, western blot detection of His-tagged thioredoxin in yeast cells, and immunohistochemistry procedures. QIAGEN recommends blocking Western Blot membranes with 3% BSA in TBS buffer when using this antibody, and switching to 10% milk powder in TBS for the secondary antibody step.