Affinity chromatography (1,2), the most powerful of all protein-fractionation techniques, relies on the formation of reversible specific complexes between a ligand immobilized on an insoluble polymer support, termed affinity adsorbent, and the species to be isolated free in solution. The modern support materials (natural, synthetic, or inorganic), consist of macroporous hydrophilic beaded particles, usually bearing free hydroxyl groups available for ligand immobilization. When the support is made of noncompressible particles of small diameter (e.g., 5-20 µm) and narrow size distribution (e.g., 0.2-2 µm) the technique is termed high-performance affinity chromatography (HPAC) (3-5).