Carbohydrate Sulfotransferase 5/CHST5: Proteins and Enzymes

The CHST family is comprised of 14 genes in both the human and mouse genomes. All members of this family are Golgi-localized type II membrane proteins. Only the luminal and enzymatic domain is expressed in each of our recombinant CHST proteins. These enzymes transfer sulfate (i.e., sulfonate) onto the 6-O or 4-O positions of GalNAc, Gal and GlcNAc residues on glycoproteins, proteoglycans and glycolipids. This sulfation often creates specific epitopes that can be recognized by extracellular matrix proteins, cell surface receptors and viruses. CHST5, also designated as I-GlcNAc6ST, GlcNAc6ST-3, and GST-4 alpha, has a marked preference for sulfating O-linked sugars of mucin type of acceptors and catalyzes the transfer of sulfate to position 6 of non-reducing GlcNAc residues on keratan sulfate. The amino acid sequence for mouse CHST5 has higher identity to that of human CHST6 (83%) than to human CHST5 (76%). Since there is no CHST6 found in the mouse genome it is possible that mouse CHST5 plays a similar biological role to the human CHST6.