Bio-Rad Profinity IMAC Resins - Manual (Page 5)

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Section 1
Introduction
Immobilized metal affinity chromatography (IMAC) is a powerful purification
technique that relies on a molecule’s affinity for certain metals immobilized onto a
chelating surface. The chelating ligand, iminodiacetic acid (IDA) in this case, may
be charged with transition metals such as Cu
2+ , Ni 2+ , Co 2+ , or Zn 2+ . This results in
the high selectivity of proteins with clustered histidine residues to be strongly
retained onto a porous chromatographic support. Jerker Porath and colleagues
first identified the role of IMAC in protein purification in the 1970s, which
incorporated the use of IDA as its chelating ligand (Porath et al. 1975). The use of
IMAC to separate an expressed recombinant protein fused with a hexa-histidine
peptide tag was demonstrated by Hochuli (1988) to yield a highly purified protein in
a single chromatographic step under both denaturing and native conditions. The
strong affinity of a histidine-tagged (His-tagged) molecule for metal ions often
makes extensive optimization unnecessary while also allowing chromatography
under conditions that denature proteins. For this reason, expression and IMAC
purification of His-tagged proteins is frequently used for structural and functional
studies of proteins.
Section 2
Product Description
Profinity ™ IMAC Resins and UNOsphere ™ Technology
Profinity IMAC resin, a unique affinity support, is based on Bio-Rad’s innovative
UNOsphere beads, which use proprietary polymerization and derivatization
technologies.* The UNOsphere technology enables the polymeric Profinity IMAC
to exhibit excellent flow properties without compromising protein binding, recovery,
or purity.
Profinity IMAC uses IDA as its functional ligand. The tertiary amine and carboxylic
acid side chains of IDA serve as the chelating ligands for di- or trivalent metal ions.
The structure offers selective binding of recombinant His-tagged proteins when this
resin is charged with Ni
2+ or other transition metals. As a result, the desired
proteins can often be purified close to homogeneity in a single step.
Structural characteristics such as the polymeric nature, optimized ligand density,
and the open pore structure of the Profinity IMAC bead result in superb mechanical
strength with high stringency, low nonspecific effects, and the ability to perform
separations at extremely fast flow rates. These unique features of the UNOsphere
base matrix lend a number of performance benefits to the Profinity IMAC resin.
*US patent 6,423,666.
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