Immobilization of protein ligands on new formyl-spacer-carriers for the preparation of stable and high capacity affinity adsorbents.

New procedures to immobilize high concentrations of protein ligands by reductive amination on two types of formyl-carriers (I & II) having different spacer lengths were investigated in order to prepare stable and high-capacity adsorbents essential for efficient affinity chromatography. Formyl-carrier (I) was prepared by reductive amination with glutaraldehyde of the amino-carrier obtained on amination of an epoxy-activated carrier. Formyl-carrier (II) was prepared by sodium metaperiodate (NaIO4) treatment of a glyceryl-carrier obtained on hydrolysis of an epoxy-activated carrier. Especially high concentrations of protein ligands were immobilized on formyl-Sepharose 4B (I) under very mild conditions (pH 7.0, 4 degrees C). A series of lectins, one of the most useful classes of group-specific ligands, was successfully immobilized by the procedures. Concanavalin A-Sepharose 4B (I) thus obtained exhibited an adsorption capacity five times greater than that of concanavalin A-Sepharose 4B made by Pharmacia Fine Chemicals, and could be repeatedly used over twenty times without a significant reduction in its adsorption capacity.