In contrast to proteins and peptides, glycans do not absorb ultraviolet (UV) light strongly, thereby giving a weak detector signal, even at 214 nm. Furthermore, as glycans with various different structures may be present in minute amounts in glycoprotein hydrolysates, their detection by UV absorbance may not be practical. As a result a wide range of alternative techniques have been developed for the detection of glycans.
Once the glycans have been released from the glycoprotein, the glycan pool can be analyzed by MALDI-TOF mass spectrometry or, after fluorescent labeling, by either HPLC or MS, or both. This strategy can provide a «glycan profile» or a «glycosylation pattern» that is highly characteristic of the glycoprotein. The technology can be applied to compare glycan profiles of glycoproteins found in normal and diseased states, or to compare different batches of recombinant protein products. Both these techniques provide valuable information in terms of composition, linkage and arm specificity.
Electrophoresis of Glycans
Separation of glycans by electrophoresis in polyacrylamide gel has been widely used and different methods are described in the literature for analysis of monosaccharides and oligosaccharides. The most commonly used system is the electrophoresis of fluorophore-labeled glycans in highly cross-linked polyacrylamide gels and is termed as Fluorophore-Assisted Carbohydrate Electrophoresis (FACE).
BiOptic's GL1000 provides an innovative solution for profiling of glycans released from glycoproteins and to elucidate the structure of individual glycans, based on the Capillary Gel Electrophoresis (CGE) technology.