Recent advances in the capillary electrophoresis of recombinant glycoproteins

Abstract

Highly efficient methods are required to analyze recombinant proteins for clinical use. These proteins generally produced from mammalian expression systems are highly glycosylated and consist of a population of glycosylated variants (glycoforms). This review presents the different microscale techniques of capillary electrophoresis (CE) for analyzing the intact recombinant glycoproteins and for monitoring their bioproduction. Because of several advantages such as simplicity, speed and automation, capillary zone electrophoresis (CZE) has been generally employed for the routine analysis of the glycoform populations of intact glycoproteins. Capillary isoelectric focusing (CIEF) is a powerful method for a charge-based separation of the glycoforms. Micellar electrokinetic capillary chromatography (MEKC) represents an alternative method to CZE for the purity control of recombinant glycoproteins, while the sodium dodecyl sulfate-capillary gel electrophoresis (SDS-CGE) with replaceable gel matrices gives an estimation of the glycoform molecular masses. The results from CIEF and SDS-CGE are comparable to those from the corresponding slab gel techniques. The recent advances in the coupling of CZE with mass-spectrometry (MS) offers new perspectives not only for precise molecular mass determinations, but also to better understand the mechanisms involved in the CE separation of glycoforms.