Bio-Rad Profinity IMAC Resins - Manual (Page 6)

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Profinity IMAC is also stable across the entire pH range (1–14) and is compatible
with most reagents commonly used in protein purifications, such as denaturants,
detergents, and reducing agents. It is amenable to separations under native or
denaturing conditions, using liquid chromatographic instrumentation, gravity flow
columns, or sample-preparation spin columns.
Note: UNOsphere media, from which Profinity IMAC is derived, was designed to
achieve the highest productivity (grams of drug or target per operational hour per
liter of support) possible. UNOsphere media may be run at the highest rates and
loading capacities while staying within the pressure limits of the column and
chromatography system.
Under optimized conditions, the binding capacity for 6xHis tagged proteins is
>15 mg/ml resin (see Table 1). The product is a 50% (v/v) slurry of resin,
suspended in a 20% ethanol solution. Profinity IMAC is amenable to process and
laboratory-scale use and is available bottled in two forms: uncharged and
precharged with Ni
2+ . Table 1 lists key characteristics of the resin, while Table 2
lists a variety of compounds compatible with Profinity IMAC.
Chemical Interactions
Profinity IMAC resin is comprised of IDA groups coupled to a UNOsphere base
matrix via a proprietary polymerization derivatization technology. It is well suited for
recombinant His-tagged purifications, and results in high binding capacity and
specificity of the target molecule.
In addition to the number of histidine, tryptophan, and cysteine residues available
for binding on a protein’s surface, efficacy of protein purification by IMAC is also
dependent on the number of coordination sites of the immobilized metal that are
not occupied by the chelating ligand, which are then free to interact with proteins
(Figure 1). In the case of Profinity IMAC Ni-charged resin, the chelating ligand is
IDA. Ni
2+ ions, which have six coordination sites bound to this tridentate chelator,
will expose three coordination sites to the environment.
Although the most commonly used metal ion for His-tagged purifications is Ni 2+ ,
other metals may be used to increase efficacy of purification. Therefore, a
concerted choice on the type of immobilized metal ions used will dictate the
selectivity of an IMAC resin.
Fig. 1. Partial structure of Profinity Ni-charged IMAC resin.
Illustration indicates UNOsphere base bead with coupled IDA
functional ligand. Wavy lines indicate available binding sites.
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