Purification and Characterization of N-Acetylglucosaminyl Sulfotransferase from Chick Corneas

Abstract

N-Acetylglucosaminyl(GlcNAc) sulfotransferase, which transfers sulfate from adenosine 3′-phosphate 5′-phosphosulfate to GlcNAc at the nonreducing end of oligosaccharides, was purified 887-fold with a 8.4% yield from 2-day-old chick corneas by chromatography on CM-Sepharose, WGA-agarose, GlcNAc-agarose, and 3′,5′-ADP-agarose columns. The purified enzyme has an optimum pH of 6.0 (Mes buffer) and specifically transfers a sulfate to GlcNAc at the nonreducing end but not to internal GlcNAc. The enzyme was stimulated by protamine and Mn2+. SDS–polyacrylamide gel electrophoresis of the purified enzyme still showed two main bands (66 and 55 kDa) with some minor bands. It appears that this enzyme competes with β-galactosyltransferase in binding to the nonreducing GlcNAc residue on KS synthesis; this suggests that the sulfation of the GlcNAc residue is coupled with the elongation of the KS chain.