Recombinant Human CHST4 Protein, CF

The CHST family is comprised of 14 enzymes in human. All members of this family are Golgi-localized type II membrane proteins (1). 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 (2). This sulfation often creates specific epitopes that can be recognized by extracellular matrix proteins, cell surface receptors and viruses (3). CHST4, also known as high endothelial cells N-acetylglucosamine 6-O-sulfotransferase (HEC-GlcNAc6ST) or L‑selectin ligand sulfotransferases (LSST), catalyzes the transfer of sulfate to position 6 of non-reducing GlcNAc residues within mucin-associated glycans that ultimately serve as L‑selectin ligands (4). It has a catalytic preference for core 2-branched mucin-type O‑glycans, but also has activity toward core 3 type of O‑glycan (5). Human CHST4 shares 72% amino acid sequence identity with the mouse ortholog.The enzymatic activity of the recombinant human CHST4 is measured using a phosphatase-coupled assay (6).