Polymerizing activity of LARGE confers ligand-binding ability on α-DG. HPLC profile of the reaction products of LARGEdTM generated from GlcA-β-MU (A) and Xyl-α-pNP (B) in the presence of both donors, UDP-Xyl and UDP-GlcA, on the amide column. S, unreacted substrate. (C) Glycoproteins extracted from Largemyd mouse skeletal muscle were incubated with LARGEdTM, with or without UDP-GlcA and UDP-Xyl, and analyzed by immunoblotting with IIH6 or the CORE antibody, or by overlay assays (OLs) using laminin-G domain–containing ECM ligands (laminin, agrin, or neurexin).