β‐Elimination for Release of O‐GalNAc‐Linked Oligosaccharides from Glycoproteins and Glycopeptides

Abstract This unit describes release of oligosaccharides that are attached to polypeptides through an N ‐acetylgalactosamine (GalNAc) linkage to the hydroxyl groups of serine or threonine. The b‐elimination procedures described here can be used to recover the oligosaccharide chains (also called glycans) and/or identify the serine or threonine residues involved in the linkage. A b‐elimination method employing sodium borohydride (NaBH 4 ) and alkaline conditions is described, and an alternative method is also presented in which only alkaline conditions are used without a reducing agent. Another alternative protocol uses sodium sulfite.