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)

Three fluorescein-labeled lectins were shown to bind differentially to cell surfaces in different epithelial layers of rat oral mucosa regardless of the age or the site of origin of the tissue. Griffonia simplicifolia (GS-1-B4), specific for alpha-D-galactosyl end groups, labeled basal cells only; Ulex europeus (Ulex 1) specific for alpha-L-fucosyl groups labeled spinous cells; and Bandeiraea simplicifolia (BSII), specific for N-acetyl-D-glucosamine, labeled cornified cells. Pretreatment of sections with alpha-galactosidase completely abolished the staining of basal cells by GS-1-B4, but had no effect on the staining of spinous cells by Ulex 1. In contrast, alpha-fucosidase abolished the staining of spinous cells by Ulex 1 and caused staining of both basal and spinous cells by GS-1-B4. Neuraminidase and chondroitinase ABC produced results similar to one another, with staining of basal cells by GS-1-B4 and labeling of both basal and spinous cells with Ulex 1. beta-galactosidase, beta-glucuronidase, and testicular hyaluronidase did not affect the staining pattern of GS-1-B4 or Ulex 1, whereas chymotrypsin completely abolished any staining with either lectin. The results demonstrate a complex arrangement of cell surface carbohydrates in the epithelium of rat oral mucosa. The findings indicate a possible simplification in the spatial arrangements of cell surface carbohydrates during the differentiation of basal to spinous cells.
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PMID:Preferential lectin binding to specific layers of rat oral epithelium and modification by enzyme pretreatment. 299 51

Chondroitin 4-sulphate, chondroitin 6-sulphate, dermatan sulphate and keratan sulphate were N-deacetylated by treatment with hydrazine and then cleaved with HNO2 at pH 4.0, and the resulting products were reduced with NaB3H4. This reaction sequence cleaved the glycosaminoglycans at their N-acetyl-D-glucosamine or N-acetyl-D-galactosamine residues, which were converted into 3H-labelled 2,5-anhydro-D-mannitol (AManR) or 2,5-anhydro-D-talitol (ATalR) residues respectively. The end-labelled disaccharides, composed of D-glucuronic acid (GlcA), L-iduronic acid (IdoA) or D-galactose (Gal) and one of the anhydrohexitols, were identified as follows: both chondroitin 4-sulphate and chondroitin 6-sulphate gave GlcA----ATalR(4-SO4), GlcA----ATalR(6-SO4), IdoA----ATalR (4-SO4) and GlcA(2-SO4)----ATalR(6-SO4); dermatan sulphate gave IdoA----ATalR(4-SO4), GlcA----ATalR(4-SO4), GlcA----ATalR(6-SO4)----IdoA(2-SO4)ATalR(4-SO4) and IdoA----ATalR (4,6-diSO4); keratan sulphate gave Gal(6-SO4)----AManR(6-SO4), Gal----AManR(6-SO4), Gal(6-SO4)----AManR and Gal----AManR. Several additional disaccharides were generated by treatment of the uronic acid-containing disaccharides with hydrazine to epimerize their uronic acid residues at C-5. A number of these disaccharides were found to be substrates for lysosomal sulphatases and glycuronidases. Methods were developed for the separation of all of the disaccharide products by h.p.l.c. The rate of N-deacetylation of chondroitin 4-sulphate by hydrazinolysis was significantly lower than the rate of N-deacetylation of chondroitin 6-sulphate or chondroitin. Dermatan sulphate was N-deacetylated at an intermediate rate. The relative amounts of disaccharides obtained from chondroitin 4-sulphate, chondroitin 6-sulphate and dermatan sulphate under optimum hydrazinolysis/deamination conditions were comparable with the amounts of the corresponding products released from the polymers by chondroitinase treatment.
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PMID:The disaccharides formed by deaminative cleavage of N-deacetylated glycosaminoglycans. 374 82

Hyaluronan is a high-molecular-weight glycosaminoglycan (GAG) prominent in the extracellular matrix. Emerging relatively late in evolution, it may have evolved to evade immune recognition. Chondroitin is a more ancient GAG and a possible hyaluronan precursor. Epimerization of a 4-hydroxyl in N-acetylgalactosamine in chondroitin to N-acetylglucosamine of hyaluronan is the only structural difference other than chain length between these two polymers. The axial 4-hydroxyl group extends out perpendicular from the equatorial plane of N-acetylgalactosamine in chondroitin. We suspect that this hydroxyl is a prime target for immune recognition. Conversion of a thumbs-up hydroxyl group into a thumbs-down position in the plane of the sugar endows hyaluronan with the ability to avoid immune recognition. Chitin is another potential precursor to hyaluronan. But regardless whether of chondroitin or of chitin origin, an ancient chondroitinase enzyme sequence seems to have been commandeered to catalyze the cleavage of the new hyaluronan substrate. The evolution of six hyaluronidase-like sequences in the human genome from a single chondroitinase as found in Caenorhabditis elegans can now be traced. Confirming our previous predictions, two duplication events occurred, with three hyaluronidase-like sequences occurring in the genome of Ciona intestinalis (sea squirt), the earliest known chordate. This was probably followed by en masse duplication, with six such genes present in the genome of zebra fish onwards. These events occurred, however, much earlier than predicted. It is also apparent on an evolutionary time scale that in several species, this gene family is continuing to evolve.
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PMID:Hypotheses on the evolution of hyaluronan: a highly ironic acid. 2331 48