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

Abstract

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.