Beta-1,3-glucuronyltransferase 3, also known as B3GAT3, is involved in forming the linkage tetrasaccharide present in heparan sulfate and chondroitin sulfate. This protein can also play a role in the biosynthesis of l2/HNK-1 carbohydrate epitope on glycoproteins. It shows strict specificity for Gal-beta-1,3-Gal-beta-1,4-Xyl, exhibiting negligible incorporation into other galactoside substrates including Galbeta1-3Gal beta1-O-benzyl, Galbeta1-4GlcNAc and Galbeta1-4Glc. Recombinant human B3GAT3 protein, fused to His-tag at N-terminus, was expressed in E.coli and purified by using conventional chromatography techniques.