Albumin immobilized on agarose as a tool for measuring ligand binding of proteins or peptides.

Bovine serum albumin immobilized on agarose has been tested in competitive binding studies as a means of measuring the binding of cortisol, tryptophan, fatty acids, and bilirubin to a number of albumins and albumin fragments. Chemical coupling of albumin to agarose does not appear to alter the primary binding sites for most ligands and the degree of ligand binding by immobilized albumin is comparable to that by soluble albumin. Evaluation of ligand binding by a protein based on its competition with immobilized protein is suggested as a convenient procedure particularly well suited to proteins and ligands whose size precludes investigation by dialysis or whose instability demands a rapid procedure.