[Characterization of stability of polypeptides and glycoproteins by capillary electrophoresis]

A capillary electrophoresis (CE) method was developed for the stability characterization of polypeptides and glycoproteins. Angiotensin II (Ang II), phytagglutinin (PHA), bovine thrombin (B-Thr), human thrombin (H-Thr) and horseradish peroxidase (HRP) were used as polypeptide and glycoprotein mode molecules. The parameters affecting the analysis efficiency for Ang II, such as sample concentration, running buffer, pH and ionic strength of sample solution were optimized, as for the glycoprotein, capillary conditions, charge state of sample, running buffer and applied voltage were optimized. It showed that the Ang II was stable when kept in borate buffer (0.02 mol/L pH 7.4) at 4 degrees C for 48 h. The four glycoproteins were quite stable in borate buffer (0.2 mol/L pH 7.4) at 20, 4, -20 degrees C for 48 h, and also kept stable at - 20 degrees C when deposited over one week and less than four weeks. HRP was the only one that kept stable when deposited over two weeks and less than four weeks. This method is effective, rapid, simple and low-cost and can be widely used for the stability characterization of polypeptides and glycoproteins.