Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.36 (hyaluronidase)
 4,606 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to investigate the coordinated synthesis of matrix components by individual chondrocytes, specific antibodies to type I collagen, type II collagen, and chondroitin sulfate proteoglycan core protein were used in simultaneous double immunofluorescence reactions. Extensive accumulation of core protein surrounding chondrocytes and the intracellular accumulation of type II collagen were observed. Extracellular core protein immunofluorescence obscured the intracellular reaction product, but the extracellular immunoreactive material could be removed by digestion with purified testicular hyaluronidase prior to fixation. Subsequent to digestion, core protein and type II collagen were observed in the same chondrocytes within discrete, sometimes identical, cytoplasmic regions, thus demonstrating the simultaneous localization of these two products characteristic of differentiating cartilage.
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PMID:Simultaneous localization of type II collagen and core protein of chondroitin sulfate proteoglycan in individual chondrocytes. 37 34

Studies of the structure and synthesis of cartilage proteoglycan core protein have been carried out. Deglycosylation of completed, secreted proteoglycan by HF-pyridine treatment yielded an intact homogeneous core protein of approximately 210,000 daltons, with a blocked amino-terminus. Greater than 95% of chondroitin sulfate chains and 80% of N- and O-linked oligosaccharides were removed by the procedure, which made the product an excellent xylosyltransferase acceptor. Little alteration of core protein structure occurred during the HF-pyridine treatment as shown by complete immunoreactivity with antiserums prepared against hyaluronidase-digested proteoglycan. In other studies, the initially synthesized precursor for proteoglycan core protein was found to be approximately 376,000 daltons and localized to the rough membrane fractions. This precursor already contained N-linked oligosaccharides, and was also able to accept xylose, thereby initiating chondroitin sulfate chains. The precursor was translocated intact in an energy-dependent manner to smooth membrane-Golgi fractions where further processing of high mannose type of oligosaccharides and addition of glycosaminoglycan chains occurred. The subcellular distribution pattern of the chondroitin sulfate-synthesizing enzymes corroborated the proposed topological modifications of the proteoglycan core protein precursor.
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PMID:Synthesis and structure of proteoglycan core protein. 391 43

Several monoclonal antibodies which recognize different antigenic determinants of chondroitin sulfate proteoglycan were used to study chondroitin sulfate proteoglycan biosynthesis in chicken chondrocyte cultures. The intracellular sites of synthesis and processing and extracellular deposition in matrix were localized by double immunofluorescence reactions. One rat monoclonal antibody, S103L , which recognizes an antigenic determinant of the core protein of the chicken cartilage chondroitin sulfate proteoglycan monomer, was used to identify both extracellular chondroitin sulfate proteoglycan and intracellular compartments containing chondroitin sulfate proteoglycan precursors. Intracellular staining with S103L was localized to perinuclear regions, and, in some chondrocytes, to a few other cytoplasmic vesicles as well. When chondrocytes were not fed for several days, intracellular chondroitin sulfate proteoglycan precursors were accumulated in larger compartments distributed throughout the cytoplasm. Polyclonal chondroitin sulfate proteoglycan antibodies displayed similar staining characteristics. In contrast, several of the monoclonal antibodies, including the rat monoclonals S11D and P100D , and the mouse monoclonals 1-B-5, 3-B-3 and 9-A-2, did not recognize native chondroitin sulfate proteoglycan, but reacted only with chondroitinase ABC-digested (and/or hyaluronidase-digested) chondroitin sulfate proteoglycan. These antibodies were particularly useful in the demonstration of the extracellular codistribution of chondroitin sulfate proteoglycan with either type II collagen or fibronectin. In other experiments, the monoclonal antibodies to chondroitin sulfate proteoglycan served to demonstrate that the perinuclear subset of intracellular compartments is uniquely involved in the addition of chondroitin sulfate oligosaccharides to the chondroitin sulfate proteoglycan core protein. Lastly, using the mouse monoclonal 5-D-4, which recognizes keratan sulfate determinants, the perinuclear region was identified as the site for keratan sulfate addition. Results suggest heterogeneity of keratan sulfate synthesis at the level of individual chondrocytes, even for cells apparently containing equivalent amounts of intracellular chondroitin sulfate proteoglycan.
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PMID:Immunofluorescence studies of chondroitin sulfate proteoglycan biosynthesis: the use of monoclonal antibodies. 620 57

Mice homozygous for the autosomal recessive gene, cartilage matrix deficiency (cmd/cmd), are characterized by disproportionate dwarfism and cleft palate. The collagen and proteoglycan of fetal limb cartilage was examined by biochemical and immunofluorescent techniques. While a normal amount of type II collagen was found, the amount of proteoglycan was reduced as determined by chemical analysis and incorporation of labeled precursors. Analyses of labeled proteoglycans by glycerol density gradient centrifugation under dissociative conditions and by gel filtration showed that the major high molecular weight proteoglycan characteristic of cartilage was absent, but smaller proteoglycans were present in normal amounts. Antibodies directed against proteoglycan core protein failed to stain the cmd/cmd cartilage while antibodies to type II collagen stained the cartilage without hyaluronidase pretreatment. Addition of beta-D-xyloside, an exogenous substrate for chondroitin sulfate synthesis, and direct assay for beta-D-xylosyltransferase activity indicated that cmd/cmd cartilage cells contained normal levels of the enzymes required for chondroitin sulfate synthesis. The data suggest that cmd/cmd is defective in the synthesis of the cartilage proteoglycan core protein.
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PMID:Absence of proteoglycan core protein in cartilage from the cmd/cmd (cartilage matrix deficiency) mouse. 724 Feb 56

Hyaluronan and chondroitin/dermatan sulfate are glycosaminoglycans that play major roles in the biomechanical properties of a wide variety of tissues, including cartilage. A chondroitin/dermatan sulfate chain can be divided into three regions: (1) a single linkage region oligosaccharide, through which the chain is attached to its proteoglycan core protein, (2) numerous internal repeat disaccharides, which comprise the bulk of the chain, and (3) a single nonreducing terminal saccharide structure. Each of these regions of a chondroitin/dermatan sulfate chain has its own level of microheterogeneity of structure, which varies with proteoglycan class, tissue source, species, and pathology. We have developed rapid, simple, and sensitive protocols for detection, characterization and quantitation of the saccharide structures from the internal disaccharide and nonreducing terminal regions of hyaluronan and chondroitin/dermatan sulfate chains. These protocols rely on the generation of saccharide structures with free reducing groups by specific enzymatic treatments (hyaluronidase/chondroitinase) which are then quantitatively tagged though their free reducing groups with the fluorescent reporter, 2-aminoacridone. These saccharide structures are further characterized by modification through additional enzymatic (sulfatase) or chemical (mercuric ion) treatments. After separation by fluorophore-assisted carbohydrate electrophoresis, the relative fluorescence in each band is quantitated with a cooled, charge-coupled device camera for analysis. Specifically, the digestion products identified are (1) unsaturated internal Deltadisaccharides including DeltaDiHA, DeltaDi0S, DeltaDi2S, DeltaDi4S, DeltaDi6S, DeltaDi2,4S, DeltaDi2,6S, DeltaDi4,6S, and DeltaDi2,4,6S; (2) saturated nonreducing terminal disaccharides including DiHA, Di0S, Di4S and Di6S; and (3) nonreducing terminal hexosamines including glcNAc, galNAc, 4S-galNAc, 6S-galNAc, and 4, 6S-galNAc.
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PMID:Microanalysis of enzyme digests of hyaluronan and chondroitin/dermatan sulfate by fluorophore-assisted carbohydrate electrophoresis (FACE). 1070 26