Studies of Drug-Protein Binding by Affinity Chromatography. II. Interactions of Bovine Serum Albumin with Various Ligands

The use of albumin immobilized on agarose gel for the characterization of drug-protein binding by means of frontal analysis affinity chromatography is described for the interaction of bovine serum albumin with a variety of ligands including hydroxybenzoic acids, warfarin, phenylbutazone, D- and L-tryptophan, sulfonamides, etc. In all the systems, the binding capacity of the immobilized albumin was increased by the presence of a six-carbon-atom spacer between the agarose gel matrix and albumin, to a level comparable to that of soluble albumin as determined by equilibrium dialysis. The effect of residual fatty acids on the binding properties of albumin was similarly examined by coupling defatted bovine serum albumin with the gel. The results indicated that there is no marked difference in binding properties between the immobilized defatted and undefatted albumin preparations. The advantages and disadvantages of the present affinity chromatographic method are discussed.