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

Improved high-performance liquid chromatographic method for N-acetylgalactosamine-4-sulfate sulfatase (arylsulfatase B) activity determination using uridine diphospho-N-acetylgalactosamine-4-sulfate

UDP-N-acetylgalactosamine-4-sulfate (UDP-GalNAc-4-S) was isolated from hen oviduct (isthmus) with a yield of 31 mumol per 100 g of wet tissue and used for arylsulfatase B (ASB) activity determination. Two HPLC methods of separation and quantitation of the reaction product were described: (1) an original gradient elution method which makes it possible to determine the reaction product when only partially purified ASB was used and additional uridine derivatives were formed during incubation; (2) an improved, fast isocratic elution method which may be used in the case of purified ASB preparations, devoid of other nucleotide hydrolysing enzymes. For both methods the detection limit was 0.1 nmol of product with standard error of determination < or = 3%. Using the gradient elution method we have found that UDP-GalNAc-4-S was hydrolysed by bovine arylsulfatase B1 most efficiently at pH 5.0 and concentration 0.5 mM with K(m) = 85 microM.

Components and proteolytic processing sites of arylsulfatase B from human placenta

Previous studies have shown that mature arylsulfatase B purified from human sources is composed of two non-identical chains with apparent molecular masses of 43 kDa and 8 kDa. Arylsulfatase B purified from human placenta in the present study, however, included another 7 kDa component that could be detected only by carbohydrate staining on reducing SDS-PAGE employing the Tris-Tricine system. The 43 kDa and 7 kDa components contained a carbohydrate moiety, but the 8 kDa one did not, as demonstrated by periodic acid-Schiff staining, Con-A lectin blotting, endo-glycosidase treatment and in vitro phosphorylation by UDP-N-acetylglucosamine: lysosomal enzyme N-acetylglucosamine 1-phosphotransferase. The purified arylsulfatase B migrated as a single polypeptide of 58 kDa on non-reducing SDS-PAGE, indicating that the three chains are linked by disulfide bonds. In order to determine the origin of the components, N-terminal sequencing of the isolated polypeptides was performed. As a result, the 43, 7 and 8 kDa components were found to commence with Ala-41, Ala-424 and Asp-466, respectively. These results suggest that after removal of the signal peptide, human arylsulfatase B undergoes proteolytic processing on at least two sites during maturation.

Arylsulphatases in the rabbit oviduct: postovulatory changes tested by histochemical and biochemical procedures

A histochemical and biochemical study of the activity of arylsulphatases A and B was carried out on the oviduct of female rabbits during the first days after mating. The histochemical results demonstrated that the ampullary and the isthmic epithelial cells have a positive reaction to the sulphatases during the whole of the postovulatory period tested. The enzymatic activity is mainly localized in the basal cellular cytoplasm. The biochemical results confirmed that both arylsulphatase A and B are active. Arylsulphatase A activity is more intense in the ampulla than in the isthmus and it increases during the whole of the postovulatory period; in the isthmus the activity increases up to 72 h, thereafter decreasing again. The arylsulphatase B activity is always lower than arylsulphatase A activity; maximum activity is reached between 66 to 72 h after mating. The arylsulphatase B is relatively higher in the ampulla than in the isthmus. The biological role of these enzymes is discussed in relation to the regulation of the sulphated glycoconjugates.

Arylsulphatases A and B in the oviduct of female rabbits in anestrus and estrus conditions

An investigation has been carried out on the activity of arylsulphatases A and B (ASA and ASB) in the oviduct of rabbits in anestrus and estrus conditions. The histochemical and biochemical results obtained have demonstrated that both arylsulphatases are present in the ampulla tract and in the isthmic one, and that the estrus determines a considerable increase in the specific activity of ASB. Hypothesis are advanced on the probable-meaning of the variations in the activity of these enzymes, particularly in relation to the secretion of glycoconjugates by the epithelium of the oviduct.

The common identity of UDP-N-acetylgalactosamine 4-sulfatase, nitrocatechol sulfatase (arylsulfatase), and chondroitin 4-sulfatase

Evidence is presented indicating that three sulfatase activities towards UDP-N-acetylgalactosamine 4-sulfate, nitrocatechol sulfate, and chondroitin 4-sulfate are functions of the same hen oviduct enzyme. Using chondroitin [35S]sulfate from chick embryo cartilage, it is shown that hydrolysis of ester sulfate by this enzyme is limited to 4-sulfate groups occurring in the non-reducing terminal N-acetylgalactosamine 4-sulfate and N-acetylgalactosamine 4,6-bissulfate residues.

The occurrence of uridine diphosphate N-acetylgalactosamine 6-sulfate in quail egg white and characteristic distribution of sulfated sugar nucleotides in different avian eggs

A sulfated sugar nucleotide has been isolated from quail egg white, and accounts for nearly 80% of the total sugar nucleotides found in the egg white. Evidence is presented that this nucleotide is uridine diphosphate N-acetylgalactosamine 6-sulfate, an isomer of the 4-sulfated derivative of uridine diphosphate N-acetylgalactosamine previously found in chicken egg white. Further studies on the distribution of sulfated sugar nucleotides in egg white of various birds (chicken, quail, pheasant, peafowl, turkey, goose, and duck) demonstrate that each species has a characteristic composition, differing from one another regarding the relative amounts of 4-sulfated, 6-sulfated, and 4,6-bissulfated derivatives of uridine diphosphate N-acetylgalactosamine.

N-Acetylgalactosamine 4,6-bissulfate in rat urine. I. Isolation, identification and chemical synthesis

By starting with 4 1 of rat urine, it was possible to obtain a sulfate ester of hexosamine in crystalline form. A series of identification procedures including chemical analyses, enzymatic digestion, proton magnetic resonance spectroscopy and infrared spectroscopy showed that this substance is 2-acetamido-2-deoxy-D-galactose 4,6-bissulfate. The trivial name for this compound is N-acetylgalactosamine 4,6-bissulfate; Quantitation by isotopic techniques indicated the urine possessed an average concentration of 8 muM N-acetylgalactosamine 4,6-bissulfate. Further extension of these studies necessitated the chemical synthesis of N-acetylgalactosamine 4,6-bissulfate and related compounds to be used for references or as biological substrates. Direct sulfation of N-acetylgalactosamine was attempted first, and strong preference for attack on the primary hydroxyl group (position 6) was found for chlorosulfonic acid. Thus, the reaction with 2.2 molar equivalents of the sulfating agent gave N-acetylgalactosamine 6-sulfate and its derivatives bearing a second sulfate at either position 1 (minor) or position 3 (major). The lack of sulfation at position 4 could be attributed to steric effects of the sulfate group preferentially attached to position 6. Another experiment in which UDP-N-acetylgalactosamine 4-sulfate was used in place of the free sugar led to the formation of a bissulfated sugar-nucleotide which, on subsequent hydrolysis with mild acid, afforded N-acetylgalactosamine 4,6-bissulfate, the same compound as that obtained from rat urine.