Column: HiTrap Protein G HP, 1 mL or 5 mL
Recommended ﬂow rates: 1 mL/min (1 mL column) or 5 mL/min (5 mL column)
Binding buffer: 0.02 M sodium phosphate, pH 7.0
Elution buffer: 0.1 M glycine-HCl, pH 2.7
Neutralization buffer: 1 M Tris-HCl, pH 9.0
Centrifuge samples (10,000 x g for 10 minutes) to remove cells and debris. Filter through a 0.45 µM filter. If required, adjust sample conditions to the pH and ionic strength of the binding buffer either by buffer exchange on a desalting column or by dilution and pH adjustment (page 133, Buffer exchange and desalting for affinity chromatography).
*Since elution conditions are quite harsh, it is recommended to collect fractions into neutralization buffer (60 µL – 200 µL 1 M Tris-HCl, pH 9.0 per mL fraction), so that the fnal pH of the fractions will be approximately neutral.
IgGs from most species and subclasses bind to protein G at near physiological pH and ionic strength. For the optimum binding conditions for IgG from a particular species, it is worth consulting the most recent literature. Avoid excessive washing if the interaction between the protein and the ligand is weak, since this may decrease the yield.
Most immunoglobulin species do not elute from Protein G Sepharose until pH 2.7 or less. If biological activity of the antibody or antibody fragment is lost due to the low pH required for elution, try Protein A Sepharose: the elution pH may be less harsh.
Desalt and/or transfer purifed IgG fractions to a suitable buffer using a desalting column (page 133, Buffer exchange and desalting for affinity chromatography).
Reuse of Protein G Sepharose depends on the nature of the sample and should only be considered when processing identical samples to avoid cross-contamination.
To increase capacity, connect several HiTrap Protein G HP columns (1 mL or 5 mL) in series. HiTrap columns can be used with a syringe, a peristaltic pump or connected to a liquid chromatography system, such as ÄKTAprime plus. For greater capacity pack a larger column with Protein G Sepharose 4 Fast Flow (Appendix 3, Column packing and preparation for affinity chromatography).
Figure 13.MAbTrap Kit, ready for use.
MAbTrap Kit contains a HiTrap Protein G HP 1 mL column, stock solutions of binding, elution and neutralization buffers, a syringe with fttings and an optimized purifcation protocol, as shown in Figure 13. The kit contains suffcient material for up to 20 purifcations of monoclonal or polyclonal IgG from serum, cell culture supernatant or ascitic ﬂuid, using a syringe. The column can also be connected to a peristaltic pump, if preferred. Figure 14 shows the purifcation of mouse monoclonal IgGfrom cell culture supernatant with syringe operation and a similar purifcation with pump operation. Eluted fractions were analyzed by SDS-PAGE as shown in Figure 15.
Figure 14.Purifcation of mouse monoclonal IgG1 from cell culture supernatant. A. with syringe operation. B. with pump operation.
Figure 15. SDS-PAGE on PhastSystem using PhastGel 10–15, non-reduced, and silver staining.
Column: HiTrap Protein G HP, 1 mL
Recommended ﬂow rate: 1 mL/min
Binding buffer: Dilute buffer concentrate 10-fold
Elution buffer: Dilute buffer concentrate 10-fold
Neutralization buffer: Add 60–200 µL of neutralization buffer per mL fraction to the test tubes in which IgG will be collected
Centrifuge samples (10,000 x g for 10 minutes) to remove cells and debris. Filter through a 0.45 µM flter. If required, adjust sample conditions to the pH and ionic strength of the binding buffer either by buffer exchange on a desalting column (page 133, Buffer exchange and desalting for affinity chromatography) or by dilution and pH adjustment.
Figure 16.Using HiTrap Protein G HP with a syringe. A: Dilute buffers and prepare sample. Remove the column’s top cap and twist off the end. B: Equilibrate the column, load the sample and begin collecting fractions. C: Wash and elute, continuing to collect fractions.
Stable in all common aqueous buffers.
Wash media and columns with 20% ethanol (use approximately 5 column volumes for packed media) and store at +4 to +8 °C.