Zonal immobilization of proteins

A gel matrix that can be used in sequence to separate proteins and then immobilize them was obtained by incorporating into agarose an aldehydic ligand with readily controllable reactivity. The gel was prepared by etherifying agarose with glycidol and subsequently oxidizing with periodate. It provided an inert matrix equivalent to ordinary agarose for separating proteins at neutral or acidic pH, but rapidly absorbed them through formation of stable alkyl amine linkages on exposure to either alkaline or concentrated NaCNBH₃. Thus, the protein could be fixed without use of denaturants. The ability to array proteins electrophoretically on an immobilizing substrate opens new possibilities for analysis of complex mixtures by providing means for carrying out affinity binding assays in relation to physical properties of the protein, and for performing multiple tests of composition without loss or spread.