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:3.2.1.36 (hyaluronidase)
4,606 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immunological and histological methods have been applied to the developing rat embryo to study the distribution of hyaluronectin (HN, a glycoprotein with hyaluronic acid-binding properties) previously shown to be present in the nervous system and in desmoplasias. HN was absent in the morula and the blastula and was first detected in the mesenchyme bordering the neural tube and somites on Day 10, i.e., at a time when hyaluronic acid is already widely dispersed in the mesenchyme. At this stage HN appeared to be closely associated with the basement membrane around the epithelial structures (somites, notochord, ectoderm) whereas the intercellular areas of mesenchyme were less strongly strained. The delineation of basement membranes decreased progressively, while the accumulation of HN increased in the cell-free areas of mesenchyme, giving a continuous, diffuse pattern. Differentiation of mesenchyme into vertebral cartilage and gut smooth muscle was accompanied by a progressive disappearance of HN. Even after streptomyces hyaluronidase or chondroitinase digestion the antigen was not unmasked in these tissues. The results are in agreement with the few observations made in the human. They suggest that HN could play a role, in association with fibronectin and glycosaminoglycans (hyaluronic acid), in the physiology of the embryonic extracellular matrix. HN appeared at a later stage in the embryonic nervous tissue; its distribution was extracellular in areas where both cell migration and proliferation occur.
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PMID:Expression of hyaluronic acid-binding glycoprotein, hyaluronectin, in the developing rat embryo. 619 26

Electron-dense material in clear synaptic vesicles in rat cerebral cortex and neuromuscular junctions of frog cutaneous pectoris muscle was demonstrated by using ferrocenyl cationics. Electron-dense spots were usually attached to the inner surface of the vesicular membrane. Control experiments (treatment with Triton X-100 or cetylpyridinium chloride; enzyme digestion with trypsin, hyaluronidase, neuraminidase, sulfatase and beta-glucuronidase) suggested that the electron-dense material is a glycoprotein.
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PMID:Demonstration of electron-dense material in clear synaptic vesicles using cationic ferrocenyl compounds. 633 45

The appearance and distribution of the extracellular material glycoprotein, fibronectin, was investigated in gastrulating chick embryos using affinity-purified anti-human plasma fibronectin antibodies. Preservation of tissue structure and immunoreactivity was carried out by ethanol/acetic acid fixation or by formaldehyde/glutaraldehyde fixation. Using the former fixation method, fibronectin immunoreactivity was detected (1) at the ventral surface of the upper layer or epiblast, mainly anterior and lateral to Hensen's node, in regions where middle-layer or mesoblast cells are not yet present, and (2) sparsely in extracellular spaces of the deep layer. Using the latter fixation method, fibronectin immunoreactivity was, moreover, found at the entire ventral surface of the upper layer, i.e., also at the epithelial-mesenchymal interface, where a basement membrane was previously described. At the light microscope level, we could not detect significant immunoreactivity in the middle layer. Treatment of sections of ethanol-fixed blastoderms with testicular hyaluronidase before immunostaining for fibronectin partially demasked the antigenic sites of this glycoprotein at the epithelial-mesenchymal interface. The present report indicates that the different regional patterns of fibronectin immunoreactivity in the basement membrane of the upper layer are spatially and temporally correlated with migration and positioning of mesoblast cells. These regional patterns are probably due to differences in the composition of fibronectin-associated material such as chondroitin sulfate A and/or C proteoglycans, and/or hyaluronate, before and after mesoblast expansion, rather than to differences in the distribution of fibronectin itself. In this respect. In this respect, it is noteworthy that the chemical composition of the basement membrane of an epithelium changes as mesenchyme cells migrate over it. The results also favor the idea that fibronectin is a structural component of the whole basement membrane which is used as a substrate for migration of mesenchymal cells.
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PMID:Expression of different regional patterns of fibronectin immunoreactivity during mesoblast formation in the chick blastoderm. 636 64

Experiments with immobilized concanavalin A strongly suggest a glycoprotein nature of three honey-bee venom enzymes, phospholipase A2, hyaluronidase and acid phosphatase. The electrophoretically and chromatographically detectable heterogeneity of phospholipase A2 results from absence of carbohydrate in a subfraction. Mannose, fucose and N-acetylglucosamine, but not galactose nor N-acetylgalactosamine, are present in the con A-binding fraction of bee venom. It is therefore concluded that only N-glycosidically linked carbohydrate occurs in bee venom glycoproteins.
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PMID:The glycoprotein nature of phospholipase A2, hyaluronidase and acid phosphatase from honey-bee venom. 665 11

Brain glycoprotein NSA3 was found to bind to immobilised hyaluronic acid. The binding was reversible and gave pure antigen (99%) in high yields (80%). The binding was suppressed by incubating the affinosorbent with hyaluronidase. It was not suppressed by trypsin. The presence of glycosaminoglycans other than hyaluronic acid in the sample did not inhibit the binding. This property is relevant to those already known for the brain glycoprotein NSA3, and to its localisation at the nodes of Ranvier. We propose to coin the name hyaluronectin for the brain glycoprotein NSA3.
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PMID:[Extraction and purification of brain glycoprotein NSA3 by binding with hyaluronic acid]. 677 20

The distribution of complex carbohydrates has been investigated cytochemically at the light and electron microscope levels in collecting ducts of the guinea pig kidney. The dialyzed iron method demonstrated acidic complex carbohydrate ultrastructurally on the outer surface of the apical and the basolateral plasmalemma of the principal cells and in their maturing Golgi cisternae and secretory granules. Glycoconjugate in these sites stained for sulfate esters with the high iron diamine method but lacked reactivity toward the periodic acid-thiocarbohydrazide-silver proteinate (PA-T-SP) sequence for visualizing vic glycol-containing glycoprotein. Lability to testicular hyaluronidase and resistance to sialidase identified the Glycosaminoglycan (GAG) in principal cell granules and the plasmalemmae as a chondroitin sulfate. In contrast, intercalated cells of the collecting ducts failed to stain with the cationic reagents, but showed light PA-T-SP reactivity demonstrative of neutral glycoprotein in the glycocalyx of the apical plasmalemma. Immunostaining with the immunoglobulin-enzyme bridge procedure localized carbonic anhydrase selectively to the intercalated cells. The ultrastructural and cytochemical observations on the guinea pig collecting ducts implicate intercalated cells in fluid and electrolyte transport and principal cells in secretion of a chondroitin sulfate to the tubule lumen and intercellular space.
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PMID:Cell specialization in collecting tubules of the guinea pig kidney: carbonic anhydrase activity and glycosaminoglycan production in different cells. 680 16

Wharton's jelly of human umbilical cord is known to contain hyaluronic acid and sulphated glycosaminoglycans (probably as proteoglycans) immobilized in an insoluble collagen fibril network. A secondary, independent, insoluble network based on glycoprotein microfibrils of 13 nm diameter and interpenetrated with the collagen network has now been found in amounts corresponding to 9% of the weight of collagen. Elastin, however, is absent. Tissue slices placed in physiological buffer swell to two-fold their in vivo volume. This is due to the influence of the polysaccharides since treatment with either testicular hyaluronidase, Streptomyces hyaluronidase or chondroitinase ABC, causes their quantitative removal and abolishes the swelling tendency of tissue. Tissue so treated remains close to its in vivo volume indicating that for this state the fibrillar network, overall, is in its relaxed unstressed configuration. Subsequent treatment with a protease causes the degradation of the glycoprotein microfibril network and a two-fold increase in tissue volume while treatment with bacterial collagenase, resulting in the solubilization of 46% of the collagen, causes only a slight deswelling. These results suggest that the unstressed configuration of the network system at the in vivo volume of tissue is due to the collagen network being held in compression by the microfibril network. With intact tissue protease digestion with trypsin, in addition, causes a preferential release of sulphated glycosaminoglycans. Hyaluronic acid, however, remains largely immobilized.
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PMID:Evidence for a mechanical coupling of glycoprotein microfibrils with collagen fibrils in Wharton's jelly. 682 35

The macromolecular basis of tissue swelling pressure and of the ability of tissue to exclude globular proteins, according to size, have been investigated using human umbilical cord. Exclusion data of tissue, and tissue from which the polysaccharides had been removed by hyaluronidase were compared. Exclusion of globular proteins by the polysaccharides, obtained by difference from the two sets of data, was similar to that reported for isolated polysaccharides in solution. It can be described by a sphere/cylinder geometric exclusion model. The exclusion behavior of the polysaccharide-free tissue was accounted for in terms of the component collagen fibrils, glycoprotein microfibrils and cells. Average pore diameters of 18 and 110 nm, respectively, for the intact tissue and for the polysaccharide-free tissue were estimated. Swelling pressure measurements were performed on intact, on hyaluronidase-treated and on hyaluronidase and then Pronase-treated tissues to obtain the contributions of the polysaccharides, of collagen and of microfibrils. Close to the in vivo volume of tissue, the swelling pressure is given almost entirely by the polysaccharides and is consistent with the osmotic pressure expected from the relative amounts of hyaluronic acid and proteoglycan present and their distribution in the extrafibrillar, extracellular space. Upon swelling or deswelling a small net contribution of the fibrillar system to the swelling pressure is evident.
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PMID:Macromolecular basis of globular protein exclusion and of swelling pressure in loose connective tissue (umbilical cord). 682 36

It has been suggested that an extracellular matrix - and cell surface - associated glycoprotein, fibronectin, plays a role in the positioning of cells in morphogenesis and in the maintenance of orderly tissue organization. In the present study the appearance and distribution of fibronectin during in ovo chick limb development has been investigated by indirect immunofluorescence techniques in H.H. stages 20-30. Fibronectin is not detectable until just prior to the transition from the morphogenetic to the cytodifferentiation phase of development. Beginning at H.H. stage 25, successive nonrandom patterns of fibronectin detection and distribution, which resemble the subsequent cartilaginous elements, precede overt chondrogenesis as detected by Alcian blue staining. This corresponds to the onset of the cytodifferentiation phase of limb development. As the accumulation of acidic proteoglycan increases in the cartilage matrix and the mesenchymal cells become more round in appearance, the presence of detectable fibronectin decreases and is ultimately seen only in the perichondria and basement membrane. However, predigestion of developed cartilage tissue with testicular hyaluronidase, prior to fibronectin staining, indicated that fibronectin remains a major constituent of cartilage matrix and is apparently masked by cartilage-specific proteoglycans. This study of chick limb development is consistent with the hypothesis that fibronectin may be a molecule that facilitates the spatial organization of cartilaginous primordia cytodifferentiation.
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PMID:Spatiotemporal patterns of fibronectin distribution during embryonic development. I. Chick limbs. 703 Nov 64

The progressive growth and eventual fusion of the atrioventricular (AV) endocardial cushions is of critical importance to normal embryonic heart development. Failure to do so would result in septal and AV valvular defects. A central feature in initial cushion growth is the migration of cushion tissue (CT) cells through an heterogeneous extracellular matrix (ECM) which has previously been shown (in particular hyaluronate) to modify migratory behavior. Attention was directed to migrating CT cells to determine if (1) their surfaces physically attach to or bind ECM and (2) are modified to suggest a morphological basis for cell:matrix interaction. The migratory appendages (filopodia) of CT cells maintained in organ culture attached both to collagenous microfibrils coated with polyanionic material and hyaluronate (HA) enriched ECM. The cell:matrix associations were of sufficient strength to restrain the cell from contracting following freezing procedures and were labile to mild trypsin treatment. HA enriched matrix persisted at the cell surface even after treatments which removed most free ECM, but was readily removed by hyaluronidase and trypsin digestion. Freeze fracture analyses revealed 16-18 nm particles elevated above the plane of the filopodial surface which closely interfaced with ECM components. These particles were variably distributed, ranging from almost homogenous dispersion to focalized clusters, but were absent on surrounding non-migratory (myocardial) cells. Results are consistent with a model in which cell attachment to its migratory substratum is mediated by polyanions (probably sulfated glycosaminoglycan and fucosylated glycoprotein) and detachment by hyaluronate.
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PMID:Endocardial cushion tissue development: structural analyses on the attachment of extracellular matrix to migrating mesenchymal cell surfaces. 703 67


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