Fig. 1. Recombinant rat C6ST-1 catalyzes sulphation of chondroitin at C-6 of GalNAc residues. (A-C) The sulphotransferase reaction was carried out with chondroitin as the acceptor substrate under conditions described in the Materials and Methods with constructs containing C6ST (A), His-C6ST (B) and His-LacZ (C). The ³⁵S-labelled product was digested with chondroitinase ACII () or chondroitinase ACII + chondro-6-O-sulphatase (^*). The digests were subjected to Partisil-10 SAX HPLC and eluted fractions were monitored for radioactivity. Arrows indicate elution positions of standard disaccharides: (1) 2-acetamide-2-deoxy-3-O-(ß-D-gluco-4-enepyranosyluronic acid)-D-galactose (Di-0S); (2) 2-acetamide-2-deoxy-3-O-(ß-D-gluco-4-enepyranosyluronic acid)-6-O-sulpho-D-galactose (Di-6S); (3) 2-acetamide-2-deoxy-3-O-(ß-D-gluco-4-enepyranosyluronic acid)-4-O-sulpho-D-galactose (Di-4S); (4) inorganic sulphate; and (5) 2-acetamide-2-deoxy-3-O-(ß-D-gluco-4-enepyranosyluronic acid)-4,6-bis-O-sulpho-D-galactose (Di-diS_E). The broken line depicts the eluting salt gradient.