Comparative Study of Macroporous Silica- and Cellulose-based Sorbents for Lectin Affinity Chromatography
AbstractPreparative lectin affinity chromatography is widely used as a first step for the isolation and purification of glycoproteins. In this work lectin affinity adsorbents for preparative processes were prepared on different macroporous matrices: silica coated with polyvinyl alcohol or its cationic derivative, and cellulose. Activation of the matrices with carbonyldiimidazole and immobilization of Concanavalin A (ConA) was studied. The chromatographic performance of prepared adsorbents was evaluated by means of glucose oxidase (GOD) adsorption isotherms and breakthrough curves. It was found that the adsorption isotherms include two steps. It was supposed that the second step might be a result of GOD dimmer adsorption from GOD solutions of a high concentration. The dissociation constant of the affinity pair was found in the magnitude of 10−6–10−7 mol L−1. Breakthrough curves showed that the sorption process on a soft cellulose-based adsorbent was highly influenced by the diffusion. Thus, the flow rate applicable for cellulose-based adsorbents should be lower than that for silica ones. In both static and dynamic GOD adsorption conditions a higher sorption capacity was obtained on the cellulose-based adsorbent, although kinetic parameters were better on silica-based ones. Moreover, despite the surface coating with hydrophilic polymers, silica adsorbents possessed high non-specific sorption of the protein.