The O-linked glycans are linear or biantennary and contain an initial GalNAc residue. O-Glycans are grouped into eight core structures, however, the most common O-glycans generally belong to core 1 and 2. These glycans are provided with a free reducing terminus (aldol), or are derivatized as a fluorescently labelled glycoside. The fluorescent labels that are commonly used are 2-AA and 2-AB.
O-glycans are present in biopharmaceuticals such as erythropoeitin (EPO), Etanercept (Enbrel) and human Factor VIII (FVIII).Core 1 and Core 2 O-glycans are also present in biopharmaceuticals such as erythropoeitin (EPO), Etanercept (Enbrel), humanFactor VIII(FVIII), Factor IX and insulin glargine.
The Ludger standards have a purity of >90% as assessed by HILIC-HPLC and can be used as internal references or system suitability standards for peak assignment during HPLC or UPLC analysis.