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:3.1.1.53 (sialidase)
2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Leu-CAMs (CD11/CD18) consisting of LFA-1, Mac-1, and p150/95 are leukocyte cell surface glycoproteins that are involved in various leukocyte functions. The asparagine-linked sugar chains were released as oligosaccharides from Leu-CAMs by hydrazinolysis. About 12 mol of sugar chains was released from 1 mol of Leu-CAMs. These sugar chains were converted to radioactive oligosaccharides by reduction with sodium borotritide and separated into neutral and acidic fractions by paper electrophoresis. All of the acidic oligosaccharides were converted to neutral ones by digestion with sialidase, indicating that they are sialyl derivatives. The neutral and sialdase-treated acidic oligosaccharides were fractionated by chromatography on lectin columns followed by Bio-Gel P-4 column chromatography. Structural studies of each oligosaccharide by sequential exo- and endoglycosidase digestion and by methylation analysis revealed that Leu-CAMs contain mainly high mannose type and high molecular weight complex type sugar chains. The latter sugar chains were of bi-, tri-, and tetraantennary complex types with the Gal beta 1----4(Fuc alpha 1----3)GlcNAc beta 1----and/or the Gal beta 1----3GlcNAc beta 1----groups together with the Gal beta 1----4GlcNAc group in their outer-chain moieties. In addition to these sugar chains, a small amount of monoantennary complex type and hybrid type sugar chains was found in Leu-CAMs. Furthermore, analysis of the asparagine-linked sugar chains released from the beta-subunit of Leu-CAMs by a series of lectin chromatography showed that subunit-specific glycosylation is not observed between the alpha- and beta-subunits of Leu-CAMs.
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PMID:Structural study of the sugar chains of human leukocyte cell adhesion molecules CD11/CD18. 167 54

The gastric and intestinal phenotypic expressions of tumor cells in 18 adenomatous hyperplasias, 33 well-differentiated adenocarcinomas, and 16 undifferentiated adenocarcinomas (4 poorly differentiated adenocarcinomas, 10 signet-ring cell carcinomas and 2 mucinous adenocarcinomas) induced by N-methyl-N'-nitro-N-nitrosoguanidine or 4-nitroquinoline-1-oxide in the rat glandular stomach were studied by histochemical stainings for mucin and immunohistochemical staining for pepsinogen isozyme 1 (Pg 1). By histochemical staining for mucin [by the paradoxical concanavalin A method, the modified method with labeled peanut lectin, the galactose oxidase-Schiff (GOS) reaction, and the sialidase-GOS reaction] and immunohistochemical staining of Pg 1, gastric cancer cells of each histological group could be clearly classified into a gastric type, including mucous neck cell pyloric gland cell, and surface mucous cell subtypes, and an intestinal type, including goblet-cell, and intestinal absorptive cell subtypes. All tumors examined in this work consisted mainly of gastric-type cells but intestinal-type tumor cells were occasionally found among the gastric-type tumor cells. The incidences of intestinal-type cells in adenomatous hyperplasias (11.1%) and small well-differentiated adenocarcinomas (28.6%) were significantly less (P less than 0.05) than that in large well-differentiated adenocarcinomas (68.4%). The incidence of intestinal-type cells in small undifferentiated adenocarcinomas (25.0%) was also less than that in large ones (58.3%). The present results suggest the occurrence of change of phenotypic expression of tumor cells from the gastric type to the intestinal type during growth of tumors.
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PMID:Cellular differentiation and histogenesis of rat glandular stomach cancers. 169 50

Platelet GMP-140, along with ELAM-1 and gp90MEL, comprise the LEC-CAM family of cell-cell adhesion proteins. The three proteins demonstrate a highly related domain organization, which includes an extracellular calcium-type lectin motif. gp90MEL, a lymphocyte homing receptor, mediates lymphocyte attachment to high endothelial venules of lymph nodes through recognition of a sialylated ligand on the endothelial cells. The rosetting of neutrophils or promyelocytic HL60 cells by activated platelets is mediated by GMP-140 on the platelets. We show here that treatment of neutrophils or HL60 cells with 3 broad spectrum sialidases completely prevents rosetting. However, the Newcastle disease virus sialidase, an enzyme specific for alpha 2,3 and alpha 2,8 linkages of sialic acid does not affect rosetting of HL60 cells. These results indicate that the ligand for GMP-140 requires sialic acid and suggest that an alpha 2,6 linkage may be critical.
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PMID:Requirement for sialic acid on neutrophils in a GMP-140 (PADGEM) mediated adhesive interaction with activated platelets. 170 Sep 7

A procedure for the detection of low activities of sialidase (= neuraminidase) is described. Natural substrates for sialidase (human erythrocytes, fetuin or gangliosides) were coated onto the wells of microplates and incubated at 37 degrees C with the enzyme. Sialidase-induced desialylation of these natural substrates unmasks saccharides that are specifically recognized by the peanut agglutinin lectin (PNA). The use of a peroxidase-conjugated PNA (Po-PNA) allowed the binding of the lectin to the desialylated substrate to be quantified. The amount of bound Po-PNA correlated directly with the amount of sialic acid released from the substrate, and therefore with the sialidase activity. With this method, it was possible to detect sialidase activity associated with bacteria, myxoviruses and cells from higher organisms. This method may have important clinical implications as the use of ELISA allows automation and concurrent analysis of numerous samples.
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PMID:An enzyme-linked lectin assay for sialidase. 171 84

IgE is highly glycosylated, but the function of the oligosaccharide side chains is largely unknown. The previous discovery of an animal lectin, IgE-binding protein (epsilon BP), affords an opportunity to study potential carbohydrate-dependent effector functions of IgE. epsilon BP is a beta-galactoside-specific lectin with binding affinity for IgE and is now known to be equivalent to carbohydrate-binding protein 35 and the Mac-2 Ag; thus, it may have multiple functions in addition to IgE binding. We have previously shown that rat r epsilon BP recognizes sialidase-treated human myeloma IgE to a much greater extent than the untreated IgE. In contrast, human epsilon BP binds essentially equivalently to a monoclonal murine IgE with or without sialidase pretreatment. To validate a possible role for epsilon BP in the IgE system, we investigated the pattern of recognition of epsilon BP for various polyclonal human IgE samples. We show that polyclonal IgE derived from four individuals with hyper-IgE syndrome or atopic dermatitis recognizes epsilon BP and that there is individual variation in the proportion of IgE recognized by epsilon BP, ranging from greater than 60% for one sample to almost undetectable levels in another. We conclude that epsilon BP does indeed recognize polyclonal IgE and that this recognition is modulated by sialylation of IgE oligosaccharides. Furthermore, there exist different IgE glycoforms, varying in the degree of sialylation, and these are distributed in a distinct manner in different individuals.
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PMID:Heterogeneous IgE glycoforms characterized by differential recognition of an endogenous lectin (IgE-binding protein). 191 4

The recognition of glycoconjugate receptors on sialidase-treated polymorphonuclear leukocytes (PMNs) by the Gal/GalNAc-reactive fimbrial lectin of Actinomyces viscosus T14V has previously been shown to initiate lactose-inhibitable phagocytosis and subsequent killing of the bacteria. Although a mutant lacking fimbriae, A. viscosus 147, was not destroyed by this mechanism, the present studies demonstrate that the deposition of C3 fragments on this bacterium by anti-A. viscosus 147 immunoglobulin M (IgM) prior to incubation with either untreated or sialidase-treated PMNs correlated with a reduction in viability of approximately 2 log10. This bactericidal activity was unaffected by lactose. A similar decrease in viability was observed following the addition of untreated PMNs to A. viscosus T14V preincubated with anti-A. viscosus 147 IgM and complement, conditions favorable for C3- but not lectin-mediated bactericidal activity. Neither IgM nor complement alone was opsonic for either strain, and individually they did not alter killing of A. viscosus T14V by sialidase-treated PMNs or inhibition of this bactericidal activity by lactose. The number of viable A. viscosus T14V cells was decreased by approximately 3.5 log10 when the bacteria were incubated with IgM and complement prior to the addition of sialidase-treated PMNs, and lactose only partially inhibited this response. Thus, the PMN-dependent bactericidal activity initiated by the participation of both the actinomyces lectin and complement was significantly greater than that achieved by either ligand alone.
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PMID:Cooperative complement- and bacterial lectin-initiated bactericidal activity of polymorphonuclear leukocytes. 198 35

Gangliosides were extracted from purified human and porcine thyrotropin (TSH) receptors (TSH-R) and were detected by probing with an 125I-labeled sialic acid-specific lectin, Limax flavus agglutinin. Gangliosides copurified with human and porcine TSH-R migrated between monosialoganglioside GM1 and disialoganglioside GD1a. Ceramide glycanase digestion of the purified human TSH-R-associated glycolipid confirmed its ganglioside nature. It was resistant to Vibrio cholerae sialidase, which digests all gangliosides except GM1, but was sensitive to Arthrobacter ureafaciens sialidase, which digests all gangliosides including GM1. These findings indicate that the human TSH-R contains ganglioside that belongs to the galactosyl(beta 1----3)-N-acetylgalactosaminyl (beta 1----4)-[N-acetylneuraminyl(alpha 2----3)]galactosyl(beta 1----4) glucosyl(beta 1----1)ceramide (GM1) family. Its intimate association with receptor protein implies a key role for ganglioside in the structure and function of the TSH-R.
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PMID:Direct evidence that ganglioside is an integral component of the thyrotropin receptor. 200 Apr 4

Lectin histochemical methods and immunohistochemical techniques have been utilized to investigate and partially characterize glycoconjugates in the developing eye. Peanut-lectin-binding sites associated with radial glial cells were found in the diencephalon. In the optic primordia, binding sites associated with radial glia were masked by terminal sialic acid, and only reacted with peanut lectin when pretreated with sialidase. This finding indicates that glycoconjugates associated with diencephalic radial glia contain terminal galactose-beta-(1----3)N-acetyl galactosamine, but glycoconjugates associated with radial glia in the optic primordia contain sialic acid----galactose-beta(1----3)N-acetyl galactosamine. The selective distribution of galactose, N-acetyl galactosamine and fucose associated with radial glial cells has also been demonstrated. We postulate that these distributions mediate the shaping of the developing eye.
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PMID:Distribution of glycoconjugates in the optic vesicle and optic cup. 207 19

For many years, molecular interactions with vascular endothelium have been studied in vitro on cultured endothelial cells. Yet, it is clear that the different environmental conditions in vivo vs. in vitro may cause phenotypic drift and altered expression of cell surface molecules. In this study, we identify several endothelial surface proteins of similar apparent molecular mass by radioiodination of cultured microvascular cells and by intravascular radioiodination of rat heart endothelium in situ. The radioiodinated surface polypeptides detected by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) (followed by autoradiography) were subjected to lectin affinity chromatography in order to provide an additional screen for identifying common surface glycoproteins and a means for partial characterization of their glycans. With a battery of 18 lectins, seven major (gp140, gp120, gp100, gp85, gp75, gp60, gp47) and 6 minor (gp330, gp300, gp180, gp160, gp150, gp42) glycoproteins were identified on the cultured cells each with a different lectin binding profile. The lectin binding profiles of many endothelial glycoproteins in situ were similar to those of their counterparts in culture. A common set of seven major glycoproteins with the same apparent molecular masses was found in situ as well as in vitro. These common glycoproteins were characterized further using both sialidase digestion and sequential lectin affinity chromatography of cell lysates. Most of the glycoproteins appear to have both complex-type N-linked and O-linked glycans except for gp60 with only O-linked glycans, gp47 with only complex N-linked sugars, and gp42 with only simple N-linked sugars. A subset of sialoglycoproteins (gp140, gp120, gp100, gp60, gp47) was identified. One of them, gp120, is podocalyxin based on immunoprecipitation with specific antiserum and another one, gp60, is a recently identified albumin binding protein on the surface of cultured microvascular endothelial cells. This study shows that gp60 is indeed present on the surface of endothelium in situ and that it is a sialoglycoprotein with typical O-linked glycans. It is apparent that the continuous type of microvascular endothelium can indeed express in culture and in situ a common set of major glycoproteins.
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PMID:Lectin analysis of common glycoproteins detected on the surface of continuous microvascular endothelium in situ and in culture: identification of sialoglycoproteins. 208 27

Structures of the N-linked oligosaccharides of a recombinant soluble form of human CD4 glycoprotein (sCD4) have been investigated by enzymic microsequencing. The glycoprotein has two N-glycosylation sites, Asn271 and Asn300, at both of which evidence for the presence of complex type biantennary sialo-oligosaccharides has been obtained previously by mass spectrometric analyses [Carr, S.A., Hemling, M.E., Folena-Wasserman, G., Sweet, R.W., Anumula, K., Barr, J.R., Huddleston, M.J. & Taylor, P. (1989) J. Biol. Chem. 264, 21,286-21,295]. Among oligosaccharides released from sCD4 by hydrazinolysis and labelled with NaB3H4, neutral (12.8%) and acidic (87.2%) oligosaccharides were detected by paper electrophoresis. The latter were rendered neutral following sialidase treatment indicating that acidity was due exclusively to the presence of sialic acid residues. By enzymic microsequencing of the sialidase-treated oligosaccharides (fractionated on affinity columns of Ricinis communis agglutinin 120 and concanavalin A) in conjunction with methylation data from the earlier study, 14 sequences were identified. These accounted for over 80% of the sialidase-treated oligosaccharides of sCD4 as follows: [formula: see text] where +/- indicates residues present on only a proportion of chains. The spectrum of oligosaccharide structures released from each glycosylation site was assessed as being similar to that of total oligosaccharides on the basis of their chromatographic profiles on the lectin columns and on Bio-Gel P-4.
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PMID:The spectrum of N-linked oligosaccharide structures detected by enzymic microsequencing on a recombinant soluble CD4 glycoprotein from Chinese hamster ovary cells. 220 9


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