Demonstration of a novel sulfotransferase in fetal bovine serum, which transfers sulfate to the C6 position of the GalNAc residue in the sequence iduronic acidα1-3GalNAcβ1-4iduronic acid in dermatan sulfate

AbstractA novel sulfotransferase activity was discovered in fetal bovine serum using pig skin dermatan sulfate as an acceptor and [35S]3′-phosphoadenosine 5′-phosphosulfate as a sulfate donor. The enzyme was separated from chondroitin:GalNAc 6-O-sulfotransferase by chromatographic techniques. Enzymatic analysis of the reaction products demonstrated that the enzyme transferred sulfate to the C6 position of the GalNAc residue in the sequence -iduronic acidα1-3GalNAcβ1-4iduronic acid-. Thus, the enzyme has been identified as a hitherto unreported dermatan sulfate:GalNAc 6-O-sulfotransferase. The finding is in sharp contrast to the current concept that in dermatan sulfate biosynthesis GalNAc 4-O-sulfation is a prerequisite for iduronic acid formation by C5 epimerase