The Enzymatic Desulfation of Sulfated Sugar Nucleotides by a Novel Sulfatase in Hen Oviduct

A soluble fraction from the isthmus region of hen oviduct catalyzes the liberation of SO42- from UDP-N-acetylgalactosamine-4-sulfate (the nucleotide that accumulates in the same tissue during egg formation). The enzyme is purified some 88-fold and is shown to catalyze the reactions: (a) UDP-N-acetylgalactosamine-4-sulfate → UDP-N-acetylgalactosamine plus SO42-; and (b) UDP-N-acetylgalactosamine-4,6-disulfate → UDP-N-acetylgalactosamine-6-sulfate plus SO42-. N-Acetylgalactosamine-4,6-disulfate is desulfated in a similar way but at approximately 13% of the rate of UDP-N-acetylgalactosamine-4-sulfate hydrolysis. The enzyme does not act upon p-nitrophenyl sulfate, N-acetylgalactosamine-4- and 6-sulfate, glucose 6-sulfate, galactose 3- and 6-sulfate, glucan sulfate, chondroitin sulfates, dermatan sulfate, keratan sulfate, heparan sulfate, and unsaturated disaccharide mono- and disulfates derived from chondroitin sulfates. There are striking differences in the sulfatase activity among the anatomically distinct regions of the oviduct: the specific activity of the isthmus extract being 7 to 12 times greater than the values of the magnum and uterus extracts. A somewhat similar activity is detected in the extracts of rat liver and kidney, but available evidence suggests that the activity in these extracts is due to the action of an arylsulfatase which is different from the isthmus sulfatase in catalyzing the cleavage of p-nitrophenyl sulfate. We previously described the occurrence in the isthmus of specific sulfotransferases which catalyze UDP-N-acetylgalactosamine-4-sulfate and UDP-N-acetylgalactosamine-4,6-disulfate formation, respectively. The present finding of a sulfatase which acts preferentially on these sulfated sugar nucleotides gives additional support to the idea that these nucleotides have an important biological role.