CRITICAL CONDITIONS FOR SEPARATING THE MICROHETEROGENEOUS COMPONENTS OF GLYCOPROTEINS BY CAPILLARY ELECTROPHORESIS

To separate the microheterogeneous components of glycoproteins, capill ary electrophoresis (CE) conditions were systematically investigated w ith ovalbumin from chicken egg white as the main testing sample. In ad dition to the well-known adsorption effect, a reversible capillary wal l partitioning effect was found to contribute greatly to the separatio n and the favorable tubing wall was that coated with polyacrylamide. T he separation media, especially the buffer composition, its concentrat ion and pH, were also found to be critical. Buffers composed of boric acid and alcohol amines were demonstrated to be more effective media t han gels and other solutions, but the selection of the buffer concentr ations and pH was dependent on samples. By using free-solution CE with polyacrylamide-coated capillaries and boric acid-alcohol amine (BA) b uffers, ovalbumin of agarose electrophoresis purity can be split into more than twenty peaks at pH 8.0+/-0.3 (0.2-0.4 mol/l BA). In contrast , free-solution CE with uncoated capillaries and gel electrophoresis w ith polyacrylamide-filled capillaries yielded only five or less peaks.