HIS-Select Information

Sigma's HIS-Select products have the ability to purify HIS-tagged proteins quickly and with high selectivity. This is made possible by the non-charged linkage chemistry that attaches the chelate to the agarose bead matrix. Most other immobilized metal affinity chromatography (IMAC) systems for HIS-tagged protein purification utilize a charged chelate linkage. Extraneous charges on the resin will attract any oppositely charged amino acid in a protein, thereby increasing non-specific binding. In addition, because the HIS-Select linker is hydrophilic, like the surface of most proteins, there is no interaction between the resin and non-specific proteins due to phobicity properties of the resin.

The highly pure tetradentate chelate feature of the resin also aids in reducing non-specific binding and higher binding capacity. Tetradentate chelates hold the metal ion at four coordination points opposed to three points like IDA type chelates. This makes the tetradentate chelate preferred over IDA type chelates because the metal ion is held tightly and this results in less metal leaching from the affinity gel.

These technologies combined, the non-charged, hydrophilic linker and the highly pure tetradentate chelate, allows HIS-Select to provide superior selectivity and binding capacity for your HIS-tagged protein. Thus, HIS-Select allows you to eliminate time-consuming secondary purification and allows for true one-step purification.

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