Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.6.4 (chondroitinase)
 2,039 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

L-[14C]Iduronic acid-containing sulfated galactosaminoglycans were formed by incubation of a fibroblast particulate fraction with UDP-D[14C]glucuronic acid, UDP-N-acetylgalactosamine, and sulfate donor (3'-phosphoadenylylsulfate). The formation of L-iduronic acid was strongly promoted by concomitant sulfation of the polymer. In the absence of sulfate donor 5 to 10% of the [14C]uronic acid residues were L-iduronic acid. However, when 3'-phosphoadenylylsulfate was included in the incubation mixture the amount of L-iduronic acid in the product increased 3 to 5-fold. Furthermore, approximately the same quantity of L-[14C]iduronic acid was recovered from the product formed in a pulse-chase experiment where incorporation of 14C-isotope preceded sulfation. It was therefore concluded that C-5 inversion of D-glucuronic acid to L-iduronic acid occurred on the polymer level as shown previously for the biosynthesis of heparin (Hook, M., Lindahl, U., Backstrom, G., Malmstrom, A., AND Fransson, L-A., J. Biol. Chem. (1974) 249, 3908). This conclusion was supported by the finding that no L[14C]iduronic acid could be detected in the UDP-hexuronic acid pool during this experiment. Nonsulfated and sulfated [14C]galactosaminoglycan products were degraded separately with chondroitinase-AC. The non-sulfated products afforded primarily disaccharide and a small amount of tetrasaccharide, while the sulfated products yielded, in addition, a considerable amount of larger oligosaccharides. Tetrasaccharides from nonsulfated products contained L-iduronic acid indicating that C-5 inversion at solitary sites can occur in the absence of sulfation of adjacent hexosamine moieties. The larger oligosaccharides obtained after chondroitinase-AC digestion of sulfated products yielded L-iduronic acid upon acid hydrolysis and were susceptible to chondroitinase-ABC digestion. The split products were almost exclusively 4-sulfated disaccharides. These results demonstrate that formation of blocks of L-iduronic acid-containing repeat periods is associated with 4-sulfation of adjacent hexosamine moieties.
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PMID:Biosynthesis of dermatan sulfate. I. Formation of L-iduronic acid residues. 112 48

The glycosaminoglycan synthesis in Furth solid mastocytoma tissue has been studied. Approx. 10% of the polysaccharide isolated after incubation in vitro with [(14)C]-glucosamine was digestible with chondroitinase ABC and the product of digestion was identified as 2-acetamido-2-deoxy-3-O-(beta-d-gluco-4-enepyranosyluronic acid)-4-O-sulpho-d-galactose. Similarly, labelling of polysaccharide in vivo with (35)SO(4) (2-) followed by isolation of mast-cell fractions by density-gradient centrifugation on colloidal silica revealed the presence of a polysaccharide which migrated as did chondroitin sulphate on electrophoresis in barium acetate. Chondroitinase ABC produced the same digestion product as before. Finally, the presence of the UDP-N-acetylgalactosamine-chondroitin 6-sulphate hexasaccharide N-acetylgalactosaminyltransferase previously implicated in chondroitin sulphate biosynthesis was demonstrated in microsomal particles from fractions of purified mast cells.
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PMID:Glycosaminoglycan synthesis in mouse mastocytoma. 426 37

Neoplastic mast cells of mice (including long-established and newly derived lines) were grown in large-volume suspension cultures to provide enough cells for preparation of microsomal fractions. Microsomal preparations from P815Y and P815S cells synthesized (14)C-labelled glycosaminoglycan when incubated with UDP-[(14)C]glucuronic acid and UDP-N-acetylgalactosamine. No significant amount of (14)C-labelled glycosaminoglycan was formed when UDP-N-acetylglucosamine was substituted for the UDP-N-acetylgalactosamine. Microsomal preparations from X163 cells synthesized (14)C-labelled glycosaminoglycan when incubated with UDP-[(14)C]glucuronic acid and either UDP-N-acetylgalactosamine or UDP-N-acetylglucosamine. The (14)C-labelled glycosaminoglycan formed in the presence of UDP-N-acetylgalactosamine was degradable by testicular hyaluronidase, indicating that it was chondroitin-like. The (14)C-labelled glycosaminoglycan formed in the presence of UDP-N-acetylglucosamine was not degradable by testicular hyaluronidase. Microsomal preparations from P815S cells were tested for sulphating activity by incubation with adenosine 3'-phosphate 5'-sulphatophosphate, as well as UDP-[(14)C]glucuronic acid, and UDP-N-acetylgalactosamine. The resulting newly synthesized polysaccharide was shown by chondroitinase ABC digestion to be 70% chondroitin 4-sulphate and 30% chondroitin. The molecular size of this newly synthesized glycosaminoglycan was determined by gel filtration to be larger than 40000 mol.wt. In general, the glycosaminoglycan-synthesizing ability of the microsomal preparations appeared to reflect glycosaminoglycan synthesis by the intact cells.
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PMID:Biosynthesis of glycosoaminoglycans by microsomal preparations from cultured mastocytoma cells. 1674 6