SALT-INDEPENDENT BINDING OF ANTIBODIES FROM HUMAN SERUM TO THIOPHILICHETEROCYCLIC LIGANDS

Several thiophilic adsorbents with mercaptoheterocyclic ligands have b een analyzed for their ability to bind human serum proteins in a salt- independent way. In contrast to 2-mercaptopyrimidine, 2-mercaptopyridi ne derived ligands show a group-selective binding of immunoglobulins a nd alpha(2)-macroglobulin, not only in the presence of high concentrat ions of sodium sulphate but in buffers with low ionic strength. The bi nding is restricted to thiophilic gels obtained by coupling 2-mercapto pyridine to a vinylsulphone-activated matrix and is not achieved on ep ichlorohydrin-activated gels. A novel thiophilic ligand based on merca ptonicotinic acid, containing a carboxylic group together with the thi ophilic pattern of thioaromatic adsorbents, is demonstrated to be usef ul as an alternative purification scheme for antibodies. (C) 1998 Else vier Science B.V. All rights reserved.