Lectin-based glycoproteomic techniques for the enrichment and identification of potential biomarkers

Glycan structures on glycoproteins are controlled by several factors such as regulated expression of glycosyltransferases and glycosylhydrolases, as well as regulation of glycoprotein expression, folding, and transport through the ER and Golgi. In cancer, for example, the glycosylation of glycoproteins can be significantly altered due to changes in the expression levels of glycosyltransferases as a result of oncogene activated signaling pathways coupled with gain or loss in chromosome copy number. Cumulatively these changes result in glycoproteins exported to the cell surface and extracellular region with altered glycan structures that can lead to significant changes in cell phenotype. Therefore, it is advantageous to be able to capture and identify proteins that express particular glycans or classes of glycans. In this report, we discuss extraction methods and lectin capture methodology that can be used to enrich and identify by mass spectrometry glycoproteins that express specific glycans that change in response to disorders or diseases, such as the presence of malignancies.