Glycosyltransferase required for the biosynthesis of heparan-sulfate and responsible for the alternating addition of beta-1-4-linked glucuronic acid (GlcA) and alpha-1-4-linked N-acetylglucosamine (GlcNAc) units to nascent heparan sulfate chains. 3-O-(beta-D-GlcA-(1->3)-beta-D-Gal-(1->3)-beta-D-Gal-(1->4)-beta-D-Xyl)-L-seryl-[protein] + UDP-N-acetyl-alpha-D-glucosamine = 3-O-(alpha-D-GlcNAc-(1->4)-beta-D-GlcA-(1->3)-beta-D-Gal-(1->3)-beta-D-Gal-(1->4)-beta-D-Xyl)-L-seryl-[protein] + H(+) + UDP Glycan metabolism; heparan sulfate biosynthesis. A soluble form is found in the serum. Ubiquitous. The soluble form derives from the membrane form by proteolytic processing. Belongs to the glycosyltransferase 47 family. Exostosin-like 2