C2 and type 2 diabetes mellitus: By contrast, the N-glycopeptides TMFPN651LTDVR-HexNAc4Hex5NeuAc1Fuc2–carrying fucosylated glycans from the C2 protein and GLN1328VTLSSTGR-HexNAc4Hex5NeuAc2 from the C4 protein were significantly up-regulated in T2D patients, which are downstream targets of C1 complex and the MASP1 protein, as well as TVLTPATNHMGN85VTFTIPANR-HexNAc2Hex7 from the C3 protein, which is the downstream target of C3 convertase.