INVESTIGATION OF MIGRATION BEHAVIORS OF PEPTIDES AND PROTEINS BY CAPILLARY ZONE ELECTROPHORESIS

In this study. using a single solvent system (30 mM sodium phosphate buffer at four different pH values: 2.0, 5.0, 7.0 and 10.0). we have investigated the migration behaviors for not only small molecules (more than 35 peptides varying in size from 2 to 42 amino acid residues and varying in charge from -1.44 to 6.93) but also large ones (more than 20 proteins varying in molecular weight from 5 kDa to 480 kDa and varying in isoelectric point from 4.1 to 11 0) Though the size (radius) of a molecule has been difficult to evaluate, it showeg best linear correlation at pH 2.0 (r 0.981). with respect to Mw (2/3) as radius of a peptide. Furthermore. it was observed that a good correlation between observed and gatculated mobility was only up to approximately 20 kDa. using Mw (273) for R and Z (calculated from the pKa of amino acid residues) at pH 2.0.