ST8SIA3

Catalyzes the transfer of sialic acid from a CMP-linked sialic acid donor onto a terminal alpha-2,3-, alpha-2,6-, or alpha-2,8-linked sialic acid of an acceptor, such as N-linked oligosaccharides of glycoproteins and glycolipids through alpha-2,8-linkages. Forms oligosialic and polysialic acid on various sialylated N-acetyllactosamine oligosaccharides of glycoproteins, including FETUB N-glycans, a2-HS-glycoprotein (AHSG) and alpha 2,3-sialylated glycosphingolipids, such as alpha 2,3-sialylparagloboside and ganglioside GM3 and to a lesser extent NCAM1 N-glycans. However, it is much more specific to N-linked oligosaccharides of glycoproteins than glycosphingolipids (By similarity). 2,3-sialylparagloboside serves as the best acceptor substrate among the glycolipids (By similarity). alpha-Neu5Ac-(2->8)-alpha-Neu5Ac-(2->3)-beta-D-Gal-(1->4)-6S-D-GlcNAc and monosialyl and disialyl N-acetyllactosamines are the best acceptor substrates among glycoproteins. May play a critical role in the striatum by mediating the formation of disialylated and trisialylated terminal glycotopes on N- and O-glycans of specific striatal proteins, regulating their distribution in lipid rafts, affecting their interaction with other binding partners, and subsequently modulating striatal functions (By similarity)..

Function from UniProtKB (O43173), read 2026-09-23. CC BY 4.0.