摘要：Molluscan hemocyanins (Hcs) have recently particular interest due to their significant immunostimulatory properties. This is mainly related to their high carbohydrate content and specific monosaccharide composition. The oligosaccharide structures of the structural subunits RvH2 from Rapana venosa hemocyanin (RvH) and βc-Helix lucorum hemocyanin (βc-HlH) were comparative investigated by mass spectrometry. Our study revealed a highly heterogeneous mixture of N-glycans with compositions Hex3-7HexNAc2-5MeHex0-4Pent0-1Fuc0-1 and Hex0-9HexNAc2-4MeHex0-1HexA0-1Pent0-1Fuc0-3, isolation from βc-HlH and RvH2, respectively. N-glycans from βc-HlH contain mainly a terminal methyl-hexose (MeHex) residue, in some cases even more than one. Several carbohydrate moieties from βc-HlH are core-fucosylated, and also possess on methylation. In contrast with RvH2, N-glycans with an internal fucose residue, substituted at two positions with N-acetylhexosamine and hexuronic acid, as and glycans containing internal fucose were not found in βc-HlH. The glycosylation sites occupancy was subsequently elucidated by precursor ion scanning of the intact glycopeptides from RvH and βc-HlH using a nano-ESI mass spectrometry and Q-trap-LC/MS system. The oligosaccharide moieties found in HlH and RvH reveal a complex N-glycan pattern combining typical structural features of different higher organisms. Moreover, they are a potential source of novel N-glycans that are important for the stimulation of the immune response and/or for the production of antibodies used in diagnosis and therapy
