RESUMEN
In the intestine, mucus covering the mucosa plays a critical role in maintaining gut homeostasis by protecting the mucosa from invasion by commensal bacteria. The gut mucus is composed primarily of MUC2 mucin secreted by goblet cells. MUC2 is highly O-glycosylated, and O-glycans are necessary for the function and polymer structure of MUC2. In addition, recent evidence revealed that several glycan modifications, such as sialylation and sulfation, confer resistance of mucins to proteolysis and affect the viscosity and lubricity of mucus. Therefore, characterizing glycan structures of mucins is required to understand their functions fully. In this chapter, we describe how to purify secreted mucins from the mammalian intestine for analysis of their glycan structures. This description includes the extraction of MUC2 mucin from the mucosal surface of the mouse colon and colon explants.