Comprehensive study on binding capacity of human immunoglobulin G to Avid AL affinity gel

Avid AL is an affinity chromatographic gel based on a synthetic ligand which has been designed for the purification of immunoglobulins. The binding capacities of the gel for human IgG were investigated under different conditions; various salts; salt concentrations; different buffer systems with pH ranging from 3.8 to 10.0; and, tissue culture supernatant supplemented with 20% serum. At a similar ionic strength, the binding capacity changed according to the salting out effect of the ions used. Kinetic parameters of the affinity adsorption showed that a strong salting out effect significantly decreased the dissociation constant. Avid AL gel purified IgG from human serum with a capacity of 26.2 mg/ml gel using binding buffer containing sodium sulfate. Recombinant Protein A gel was used as a control. In this study it also exhibited enhanced binding capacity with a high salt concentration binding buffer.