CHARACTERIZATION OF A NOVEL MUCIN SULFOTRANSFERASE ACTIVITY SYNTHESIZING SULFATED O-GLYCAN CORE 1,3-SULFATE-GAL-BETA-1-3GALNAC-ALPHA-R

A novel sulphotransferase (sulpho-T) activity from rat colonic mucosa was characterized using O-glycan core 1 substrate, Gal beta 1-3GalNAc alpha-benzyl. Derivatives of Gal beta 1-3GaINAc- were used to demonstr ate that the 3- and 4-hydroxyl of Gal and the 2-acetamido group of the GalNAc residue of Gal beta 1-3GalNAc alpha-benzyl substrates were imp ortant for activity, Sulphated product using Gal beta 1,3GalNAc alpha- benzyl as substrate was analysed by ion spray mass spectrometry, methy lation analysis, high-pH anion-exchange chromatography and beta-galact osidase digestion, The results suggested that sulphate was added to th e 3-position of the Gal residue, The synthesis of core 2 from core 1 b y UDP-GlcNAc: Gal beta 1-3GalNAc beta 6-GlcNAc-transferase was inhibit ed by sulphation of the Gal residue, indicating that GlcNAc beta 1-6 b ranching has to precede sulphation in the O-glycan core 1 processing p athway. These data demonstrate several novel pathways in the synthesis of sulphated mucin-type oligosaccharides.