Galactosylgalactosylxylosylprotein 3-beta-glucuronosyltransferase 3 (B3GAT3)

Glycosaminoglycans biosynthesis (PubMed:25893793). Involved in forming the linkage tetrasaccharide present in heparan sulfate and chondroitin sulfate.

Transfers a glucuronic acid moiety in the uridine diphosphate-glucuronic acid (UDP-GlcUA) to the frequent linkage region trisaccharide Gal-beta-1,3-Gal-beta-1,4- Xyl covalently bound to a Ser residue in the glycosaminylglycan attachment site of proteoglycans. Can also play a role in the biosynthesis of l2/HNK-1 carbohydrate epitope on glycoproteins.