N-Glycoprofiling of immunoglobulin G and lactoferrin with site-specificity from goat milk using RP-UHPLC MS/MS

Glycans present in glycoproteins are structurally diverse and contribute to the carbohydrate pool of the milk. Goat milk is a leading non-bovine milk source, wherein glycan diversity of several glycoproteins remains unexplored. Herein, site-specific N-glycoprofiling of two major glycoproteins - immunoglobulin G (IgG) and lactoferrin (Lf) from goat milk was performed through RP-UHPLC Q-Tof MS/MS approach. IgG revealed diverse complex glycans that were predominantly biantennary type with differential core fucosylation, bisecting GlcNAc, and mono/di- sialylation (NeuAc/NeuGc). The N-glycan repertoire of Lf at four sites indicated the range of high mannose, complex and hybrid types with varying abundances. High mannose glycans were specifically observed at N₂₅₂NT and N₅₆₄DT sites. Majorly complex glycans with fully sialylated were found at N₃₈₇VT site. While N₄₉₅QT site revealed complex and hybrid types with differential core fucosylation and sialylation. The glycan features observed in these glycoproteins would pave way for effective utilization as bioactive ingredients.