CYCLODEXTRIN AIDED SEPARATION OF PEPTIDES AND PROTEINS BY CAPILLARY-ZONE-ELECTROPHORESIS

Carboxymethylated-beta-cyclodextrin (CMBCD) in the electrophoretic med ium (aqueous 50 mM sodium phosphate, pH 2.5) enhanced the separation u sing raw fused-silica capillaries in CZE of the four standard proteins : alpha-chymotrypsinogen A, cytochrome c, lysozyme and ribonuclease A. Furthermore, with 20 mM CMBCD in the electrophoretic medium, the cis- trans isomers of angiotensin could be separated at room temperature, w hereas the separation of the conformers required subambient temperatur es as low as -20 degrees C without CMBCD in the electrophoretic medium [50 mM sodium phosphate (pH 2.5), containing 10% (v/v) methanol]. Add ition of heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DMBCD) had no ef fect on the separation of the above proteins and peptides. The results suggest that in microcolumn separation techniques, certain cyclodextr in additives can be useful selectivity enhancers. (C) 1998 Elsevier Sc ience B.V.