An investigation into the mechanism of electrophoretic desorption of immunoglobulin G from protein A-Sepharose

Immunoaffinity chromatography using electroelution

Immunoaffinity chromatography and electroelution of protein from solid-phase matrices are two powerful tools often used to purify proteins. In this study, we combined these two techniques and found that antigen was effectively recovered from immunoaffinity resins by electroelution. Yields ranged from 90.5% to 62.8%, with a mean of 74.0 +/- 7.4% (mean +/- standard deviation). A major portion of the eluate, 79.4 +/- 13.1%, was concentrated in a volume of 100 microliters and 94.0 +/- 2.0% was recovered in 200 microliters, even when 1 ml of resin was used. Electroelution had no major effect on the electrophoretic mobility of the antigen. Two distinct antigens, a relatively hydrophilic 230-kDa protein and a hydrophobic 28-kDa protein were successfully electroeluted. In addition two types of immunoaffinity resins, monoclonal antibody covalently linked to CNBr-activated Sepharose or immobilized protein A, were found to be compatible with this method.

Isotachophoretic electrodesorption of proteins from an affinity adsorbent on a microscale

Cationic isotachophoresis was used for the desorption of mouse monoclonal antibody to transferrin strongly affinity-bonded to transferrin immobilized on polyethyleneglycol terephthalate powder. The electrodesorption under nondestructive conditions was effected in the capillary isotachophoresis apparatus of our own construction which was equipped with an adsorption element. The electrodesorption is on-line connected with quantitative isotachophoretic analysis of the antibody desorbed. Only a few tens of microliters of the affinity adsorbent and several nanomoles of the antibody are needed for the characterization of the capacity of the affinity adsorbent and the conditions of adsorption and desorption.