chondroitin-sulfates and sulfur-trioxide

The specificities of glycosaminoglycan (GAG) modification enzymes, particularly sulfotransferases, and the locations and concentrations of these enzymes in the Golgi apparatus give rise to the mature GAG polysaccharides that bind protein ligands. We studied the substrate specificities of sulfotransferases with a stable isotopically labeled donor substrate, 3'-phosphoadenosine-5'-phosphosulfate. The sulfate incorporated by in vitro sulfation using recombinant sulfotransferases was easily distinguished from those previously present on the GAG chains using mass spectrometry. The enrichment of the [M + 2] isotopic peak caused by (34)S incorporation, and the [M + 2]/[M + 1] ratio, provided reliable and sensitive measures of the degree of in vitro sulfation. It was found that both CHST3 and CHST15 have higher activities at the non-reducing end (NRE) units of chondroitin sulfate, particularly those terminating with a GalNAc monosaccharide. In contrast, both NDST1 and HS6ST1 showed lower activities at the NRE of heparan sulfate (HS) chains than at the interior of the chain. Contrary to the traditional view of HS biosynthesis processes, NDST1 also showed activity on O-sulfated GlcNAc residues.

Topics: Carbohydrate Sulfotransferases; Chondroitin Sulfates; Chromatography, Liquid; Glycosaminoglycans; Heparitin Sulfate; Mass Spectrometry; Substrate Specificity; Sulfotransferases; Sulfur Isotopes; Sulfur Oxides

Several samples of oversulfated chondroitin and dermatan were obtained by chemical sulfation and by SAX-HPLC enrichment. The starting products and oversulfated products were tested as potential inhibitors of human leukocyte elastase, an enzyme hypothesized to be involved in the etiology of diseases such as emphysema, atherosclerosis, and rheumatoid arthritis. Chemical oversulfation (SO3H/COOH 1.6-3.2), preferentially occurring at C-6 of galactosamine residues, was found generally to increase the inhibitory power on elastase. Chemically oversulfated galactosaminoglycans thus have potential as therapeutic agents, considering that they produce non-significant effects on the hemocoagulative system. Two naturally oversulfated dermatans sulfate (SO3H/COOH ca. 1.2), mainly oversulfated at C-2 of iduronic acid residues, showed comparatively higher anticoagulant activity (in the HC-II mediated thrombin inhibition test).

Topics: Animals; Blood Coagulation; Carbohydrate Sequence; Cartilage; Cattle; Chondroitin Sulfates; Dermatan Sulfate; Enzyme Inhibitors; Humans; Leukocyte Elastase; Leukocytes; Molecular Sequence Data; Molecular Structure; Pancreatic Elastase; Polysaccharides; Sharks; Sulfates; Sulfur Oxides