Sialyltransferases, such as ST6GAL2 (EC 2.4.99.1), are type II transmembrane proteins that catalyze the transfer of sialic acid from CMP-sialic acid to an acceptor carbohydrate, usually to the terminal ends of carbohydrate chains.[supplied by OMIM].
Transfers sialic acid from the donor of substrate CMP-sialic acid to galactose containing acceptor substrates. Has alpha-2,6-sialyltransferase activity toward oligosaccharides that have the Gal-beta-1,4-GlcNAc sequence at the non-reducing end of their carbohydrate groups, but it has weak or no activities toward glycoproteins and glycolipids.