Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Monoclonal antibody Cat-301 was previously shown to recognize a surface-associated antigen on subsets of mammalian CNS neurons whose expression is regulated by neuronal activity early in an animal's postnatal life. We now present the partial purification and characterization of the Cat-301 antigen and demonstrate that it is a chondroitin sulfate proteoglycan. Extracellular localization of the Cat-301 epitope is demonstrated by staining live, intact neurons in situ. Extraction of the antigen from membranes in the absence of detergent indicates that it is either a peripheral membrane protein or a component of an extracellular matrix. The Cat-301 antigen migrates on Western blots of SDS gels with a molecular weight of integral of 680,000 dalton and is purified by DEAE chromatography and Sepharose gel filtration in 8 M urea (pH 4.9) buffer. The antigen is sensitive to chondroitinase ABC, indicating that it is a chondroitin sulfate proteoglycan. Furthermore, we provide strong evidence that the biochemically characterized antigen is indeed the histologically detected species by using a second antibody, Cat-304, that produces immunohistological staining patterns identical to those of Cat-301 and reacts with the purified antigen, but at a distinct epitope. Our earlier developmental findings and the present localization and biochemical results suggest that the antigen may play a role in the maturation of functional connections between neurons, perhaps through stabilization of axosomatic and axodendritic synapses.
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PMID:Characterization of an activity-dependent, neuronal surface proteoglycan identified with monoclonal antibody Cat-301. 262 46

The effects of the enzymes collagenase, pepsin, chondroitinase ABC and keratanase on the polypeptide composition of the mammalian tectorial membrane have been analysed using one dimensional SDS-polyacrylamide gel electrophoresis (SDS-PAGE). After reduction at least ten polypeptides can be consistently and clearly recognized in SDS gels with molecular weights relative to globular protein standards of 245, 235, 190, 165, 155, 145, 100, 93, 60-73 and 35-49 kDa. With the exception of the 60-73 and 35-49 kDa bands all these polypeptides are sensitive to digestion with bacterial collagenase. The 235, 165, 155, 145 and 93 kDa bands also resist degradation by cold, acidic pepsin. Amino acid analysis of whole tectorial membranes demonstrates that glycine accounts for nearly 25% of the total amino acid content, that proline, hydroxyproline and hydroxylysine are present and that amine sugars can be detected in fairly high concentrations. Estimates based on hydroxyproline content suggest that collagens account for 25-50% of the total tectorial membrane protein. Immunoblotting techniques demonstrate the presence of polypeptides cross reacting with antisera to Type II collagen, Type IX collagen and Type V collagen. Results from immunohistochemical studies confirm that these polypeptides are present in the tectorial membrane and are not contaminants of the isolation procedure. Collagenase treatment of tectorial membranes reveals the presence of an additional non-collagenous polypeptide with an apparent molecular weight of 173 kDa on 7.5% polyacrylamide gels, and polydisperse high molecular weight material spreading over a broad range at the top of the gels. This high molecular weight material and the 173, 60-73 and 35-49 kDa non-collagenous polypeptides are pepsin sensitive and all bind wheat germ agglutinin (WGA) suggesting that they contain N-acetyl glucosamine. The 173 kDa band also binds soybean agglutinin (SBA) suggesting the presence of N-acetyl galactosamine. In the absence of reducing agent the 173 and 60-73 kDa bands are no longer observed and high molecular weight material forming a broad band at the top of the separating gel is seen. The electrophoretic behaviour of this non-collagenous, glycosylated, disulphide bonded, high molecular weight material is altered by treatment with keratanase but not by chondroitinase ABC. The results of this study indicate the tectorial membrane contains at least three different collagen types and, in addition to these collagenous proteins, several non-collagenous, glycosylated polypeptides that may account for as much as 50% of the total tectorial membrane protein.
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PMID:Polypeptide composition of the mammalian tectorial membrane. 354 19

Extraction of rat glomerular basement membrane, purified by osmotic lysis and sequential detergent treatment, with 8 M urea containing protease inhibitors solubilizes protein that is devoid of hydroxyproline and hydroxylysine. This material represents 8-12% of total membrane protein, elutes mainly as two high molecular weight peaks on agarose gel filtration, and is associated with glycosaminoglycans. Isolated rat renal glomeruli incorporate [35S]sulfate into basement membrane from which this non-collagenous 35S-labeled fraction can be subsequently solubilized. The radioactivity incorporated into urea-soluble glomerular basement membrane eluted primarily with the higher molecular weight peak (Mr greater than 250 000). Cellulose acetate electrophoresis after pronase digestion of the urea-soluble fraction revealed glycosaminoglycan that was resistant to digestion with Streptomyces hyaluronidase and chondroitinase ABC, sensitive to nitrous acid treatment, and contained [35S]sulfate. The findings indicate that one of the non-collagenous components of glomerular basement membrane is a proteoglycan containing heparan sulfate.
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PMID:Non-collagen protein and proteoglycan in renal glomerular basement membrane. 731 55

Certain constitutive skin basement membrane components, such as bullous pemphigoid antigens and epidermolysis bullosa acquisita antigen, were discovered because they were targeted by an autoimmune reaction. We aimed to purify and characterize a 105-kDa skin basement membrane protein termed p105 recognized by autoantibodies (anti-p105) from patients with a unique immune-mediated subepidermal blistering skin disease. A simian virus 40-transformed human fibroblast cell line that synthesizes and secretes p105 was utilized as the protein source. p105 was partially purified by salt-gradient fractionation of serum-free conditioned medium through a Mono Q anion-exchange column and by examining each fraction with protein staining and immunoblotting against anti-p105. p105 was isolated from polyacrylamide gel electrophoresis gels, blotted onto polyvinylidene difluoride membrane, and subjected to protein microsequencing. The 20 microsequenced N-terminal amino acids exhibited no homology to known basement membrane proteins but exhibited a 70% homology to a 90-kDa tumor-associated antigen. Antibodies raised against a peptide generated from these amino acid sequences reacted to a 105-kDa western-blotted keratinocyte and fibroblast protein and a basement membrane component. p105 resisted digestion by glycosidases chondroitinase ABC, neuraminidase, and N-glycosidase F but was cleaved by protease V8 to antigenic fragments of 22 kDa and 14 kDa. The synthesis of p105 was inhibited by cycloheximide. We conclude that p105 is a unique basement membrane component produced by both keratinocytes and fibroblasts.
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PMID:The 105-kDa basement membrane autoantigen p105 is N-terminally homologous to a tumor-associated antigen. 875 64

Recent studies have identified a specific membrane protein in osteoblast-like cells which binds intact and carboxy-truncated IGFBP-5 with high affinity. The purpose of the present study was to evaluate the IGFBP-5 binding properties of osteoblast-derived extracellular matrix (ECM), with special interest in determining whether ECM proteoglycans were necessary for IGFBP-5 binding. Neonatal mouse osteoblasts and the ECM of these cells both bound intact [125I]IGFBP-5 and [125I] IGFBP-5(1-169), though the ECM bound both forms with lower affinity when compared to their cellular binding. Treatment of the ECM with heparinase or chondroitinase, to remove glycosaminoglycan (GAG) side-chains of proteoglycans, resulted in 20-34% enhanced binding of intact [125I]IGFBP-5 and a 92-100% enhancement of [125I]IGFBP-5(1-169) binding. Similar enzymatic treatment of osteoblast monolayers had no effect on the binding of either form of [125I]IGFBP-5. These results indicate that GAGs within ECM secreted by neonatal mouse osteoblasts do not mediate the binding of IGFBP-5. This study also shows that intact and carboxy-truncated IGFBP-5 preferentially bind to the osteoblast surface, but that removal of GAGs from osteoblast-derived ECM can increase IGFBP-5 localization to this pericellular space, particularly the carboxy-truncated form of IGFBP-5.
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PMID:Comparison studies of IGFBP-5 binding to osteoblasts and osteoblast-derived extracellular matrix. 881 77

Chlamydial attachment to columnar conjunctival or urogenital epithelial cells is an initial and critical step in the pathogenesis of chlamydial mucosal infections. The chlamydial major outer membrane protein (MOMP) has been implicated as a putative chlamydial cytoadhesin; however, direct evidence supporting this hypothesis has not been reported. The function of MOMP as a cytoadhesin was directly investigated by expressing the protein as a fusion with the Escherichia coli maltose binding protein (MBP-MOMP) and studying its interaction with human epithelial cells. The recombinant MBP-MOMP bound specifically to HeLa cells at 4 degrees C but was not internalized after shifting the temperature to 37 degrees C. The MBP-MOMP competitively inhibited the infectivity of viable chlamydiae for epithelial cells, indicating that the MOMP and intact chlamydiae bind the same host receptor. Heparan sulfate markedly reduced binding of the MBP-MOMP to cells, whereas chondroitin sulfate had no effect on binding. Enzymatic treatment of cells with heparitinase but not chondroitinase inhibited the binding of MBP-MOMP. These same treatments were also shown to reduce the infectivity of chlamydiae for epithelial cells. Mutant cell lines defective in heparan sulfate synthesis but not chondroitin sulfate synthesis showed a marked reduction in the binding of MBP-MOMP and were also less susceptible to infection by chlamydiae. Collectively, these findings provide strong evidence that the MOMP functions as a chlamydial cytoadhesin and that heparan sulfate proteoglycans are the host-cell receptors to which the MOMP binds.
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PMID:A recombinant Chlamydia trachomatis major outer membrane protein binds to heparan sulfate receptors on epithelial cells. 885 23

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