BPX^TM Ds20-Ni IDA : Cat.#DSP-20-05

BPX^TM Ds20-Ni IDA are prepacked WorkBeads 40 IDA (high) columns pre-loaded with Ni⁺², a high throughput agarose media for Immobilized Metal Affinity Chromatography (IMAC) designed for capture or intermediate purification steps.

• Choice of IMAC Chemistry to Fit a Large Variety of Proteins
• High Precision and High Flow Characteristics by using 40μm
• Made from Agarose, Well Established and Well-known in the Biotechnology Industry
• The well-known Iminodiacetic acid (IDA) used for chelator and preloaded with Ni⁺².
• High flow rates and high capacities
• Easy & predictable scale-up
• Compatible design for use with syringes, single laboratory pump, or chromatography system

Metal Ions and Loading

The following metal ions have been used most fre-quently for IMAC: Zn²⁺, Cu²⁺, Ni²⁺, Fe³⁺, Co²⁺, Ca²⁺ and Al³⁺ but in principle all metal ions known to interact with proteins can be used. It should be noted that the total capacity for the dif-ferent gels are specified only for Cu²⁺ and will vary slightly for other metal ions. A 50 mM solution of a suitable metal is prepared in distilled water. Some care has to be taken when selecting the loading buffer. The concentration of metal ion will be rather high when absorbed to the gel and precipitation may occur. Normally a 0.1 M sodium acetate buffer pH 5.5 can be used. The metal salt solution is added through a sample loop by repeated injection until the gel is fully loaded.

Adsorption and Desorption Conditions

These conditions vary of course with the separation problem. Adsorption solvents are normally aqueous but organic solvents in low concentration can also be used. Depending on the nature of the chelator both electrostatic forces and hydrophobic interaction may be involved and care has to be taken with the ionic strength of the buffer. Buffers containing groups with affinity for the metal ion should be avoided (e.g. imidazole.)  Protein desorption is either done by change of the pH or by competition for the metal binding sites between the protein and another compound like ammonium salts or imidazole buffer.

Removal of Metal Ions

Many metal ions undergo redox reactions and this may cause deviations during storage of the gel. If the gel is not going to be used for a long time, the removal of metal ions is strongly recommended. This is easily done with 0.1 M solution of ethylenediamine tetra acetic acid (EDTA) either through repeated injec-tion via e.g. a sample loop or directly through the pump.