HS3ST4

HS3ST4 encodes heparan sulfate-glucosamine 3-sulfotransferase 4. HS3ST catalyzes the sulfation at C3 position of GlcNAc, the later reaction in the heparan sulfate biosynthetic pathway. There are seven isoenzymes of HS3ST in humans, which differ in expression tissues and substrate specificity. HS3ST1 and HS3ST5 transfer sulfate to the hydroxyl group at the C3 position of N-sulfo-glucosamine (GlcNS±6S) with GlcA or IdoA attached to the non-reducing terminal side. HS3ST2, 3A, 3B, 4, 5 and 6 transfer sulfate to the C3 position of Glucosamine (GlcNH2±6S or GlcNS±6S) with IdoA2S attached to the non-reducing terminal side.