A novel method to clean protein G agarose for affinity column matrix with renewed binding capacity and high IgG...

Attempts have been made at finding ways of cleaning used protein G agarose to revive their efficiency and make them reusable for purifying immunoglobulin G (IgG) in affinity column chromatography. A successful cleaning procedure that involved the use of 4-mol/L urea with 0.1-mol/L sodium hydroxide has been previously evaluated although it had some deleterious effect on the column binding capacity and compromised the resin efficiency. Efforts to develop base-tolerant affinity columns by using genetically engineered ligands such as the recombinant protein A from GE Healthcare have achieved some progress, with the column efficiency getting compromised to a lesser extent. However, genetically engineered ligands are even more expensive and may not be readily affordable in modest laboratory settings, especially if large-scale purchases are needed in routine use. We report here a novel and simple cleaning method involving the use of polyethylene glycol (PEG8000) that renews matrix-binding capacity comparable to a new resin while retaining high selectivity for IgG.