Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.1.53 (sialidase)
 2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recognition of receptors on sialidase-treated polymorphonuclear leukocytes (PMNs) by the Gal/GalNAc lectin associated with the type 2 fimbriae of certain strains of actinomyces results in activation of the PMNs, phagocytosis, and destruction of the bacteria. In the present study, plant lectins were utilized as probes to identify putative PMN receptors for the actinomyces lectin. The Gal-reactive lectin from Ricinus communis (RCAI), the Gal/GalNAc-reactive lectins from R. communis (RCAII) and Bauhinia purpurea (BPA), as well as the Gal beta 1-3GalNAc-specific lectins from Arachis hypogaea (PNA) and Agaricus bisporus (ABA) inhibited killing of Actinomyces naeslundii WVU45 by sialidase-treated PMNs. These five lectins detected a 130-kDa surface-labeled glycoprotein on nitrocellulose transfers of PMN extracts separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This glycoprotein was revealed only after treatment of the transfers with sialidase, a condition analogous to the sialidase dependence of the lectin-mediated biological responses of the PMNs to the actinomyces. The mannose-reactive lectin concanavalin A did not inhibit killing of the actinomyces and failed to detect the 130-kDa glycoprotein but did block PMN-dependent killing of Escherichia coli B, a bacterium that possesses mannose-sensitive fimbriae. Therefore, the PMN glycoprotein receptor for A. naeslundii is clearly distinct from those recognized by E. coli. Two major putative glycolipid receptors were also identified by actinomyces and RCAI overlays on sialidase-treated thin-layer chromatograms of PMN gangliosides. Thus, both a 130-kDa glycoprotein and certain gangliosides are implicated in the attachment of the actinomyces to PMNs.
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PMID:Putative glycoprotein and glycolipid polymorphonuclear leukocyte receptors for the Actinomyces naeslundii WVU45 fimbrial lectin. 779 78

Mammalian oocytes are surrounded by an extracellular glycocalyx, the zona pellucida (ZP). In the mouse, the ZP is composed of three glycoproteins, designated mZP1, mZP2, and mZP3. Extensive studies in this species have resulted in the identification of primary (mZP3) and secondary (mZP2) receptors for spermatozoa. In this paper we present evidence for the occurrence of poly-N-acetyllactosaminyl glycans and an O-linked trisaccharide on mZP2 and mZP3. When exhaustively digested with endo-beta-galactosidase, an enzyme known to cleave repeating units of acetyllactosamine (3Gal beta 1, 4GlcNAc beta 1), mZP2 and mZP3 showed an apparent reduction in size by 23 kDa and 16 kDa, respectively. Experimental evidence included in this report indicates that polylactosaminyl glycans are present on N-linked sugar chains. In addition, O-linked sugar chains of mZP3 have been characterized. First, treatment of de-N-glycosylated mZP3 with O-glycanase in the presence of exo-glycosidases (sialidase, alpha-L-fucosidase, and N-acetylglucosaminidase) caused an apparent reduction in its size by 2-3 kDa as determined by SDS-PAGE. Second, treatment of the de-N-glycosylated mZP3 with mild alkali in the presence of 1 M NaB3H4 released radiolabeled oligosaccharide (OS) that eluted from a high-resolution Bio-Gel P-4 column at the position of a trisaccharide. The radiolabeled OS had the following structure: GlcNAc-->Gal beta 1,3GalNAcol. The structure was established by sizing on the Bio-Gel P-4 column, followed by examination of the susceptibility of the OS to exo-glycosidases and by its absorbability to immobilized lectin (PNA). Potential roles of N-linked and O-linked sugar chains in sperm-egg interaction are herein discussed.
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PMID:O-linked trisaccharide and N-linked poly-N-acetyllactosaminyl glycans are present on mouse ZP2 and ZP3. 794 82

N-Acetyl-lactosamine(beta-D-Gal p-(1-->4)-D-Glc pNAc) was synthesized regioselectively with the aid of the transglycosylation activity of beta-galactosidase isolated from Diplococcus pneumoniae using p-nitrophenyl beta-D-galactopyranoside as the donor. Also, transglycosylation of the sialyl group in an alpha-(2-->8)-linked sialic acid dimer or p-nitrophenyl glycoside of sialic acid to N-acetyl-lactosamine was performed using sialidases of various origins. When sialidase from Clostridium perfringens, Arthrobacter ureafaciens, or Vibrio cholerae was used, alpha-(2-->6)-linked sialyl N-acetyl-lactosamine was obtained regioselectively. In contrast, when sialidase from newcastle disease virus was used, the alpha-(2-->3)-linked isomer was obtained regioselectively. The regioselectivity of the transglycosylation reaction using beta-galactosidase and sialidase was compared with hydrolysis specificity toward the same linkages.
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PMID:Regioselective transglycosylation in the synthesis of oligosaccharides: comparison of beta-galactosidases and sialidases of various origins. 803 89

The target molecules on the cell surface of Trypanosoma cruzi trypomastigotes reacting with lytic anti-alpha-galactosyl antibodies from chronic patients with Chagas' disease (Ch anti-Gal) have been purified by solvent extraction and identified as glycoconjugates migrating in the 74-96-kDa range (F2 antigen) and in the 120-200-kDa range (F3 antigen) on SDS-PAGE. The F3 antigen was tested for binding to Ch and normal human serum (NHS) anti-Gal and to MoAb 3C9. We observed that Ch anti-Gal and MoAb 3C9, but not NHS anti-Gal, bind strongly to the trypomastigote glycoconjugates. These antibodies, however, did not compete with each other for binding to F3 molecules, indicating that they are recognizing different epitopes. Binding of Ch anti-Gal to F3 antigen is abolished by treatment of these molecules with alpha- but not beta-galactosidase. Binding of 3C9 MoAb is abolished by treatment of F3 with sialidase. F2/F3 antigens absorbed Ch anti-Gal as well as lytic antibodies from total chagasic sera. These antigens also specifically discriminate between the serum reactivity of patients with active Chagas' disease and those of sera from cured patients, drug-treated patients with dissociated serology (positive conventional serology, negative trypanolytic activity), healthy individuals, and patients with several other infectious diseases. We also observed that F2/F3 antigens are anchored to the parasite membrane via glycosylphosphatidylinositol (GPI). The alpha-galactosyl epitopes recognized by Ch anti-Gal are present in a series of O-linked oligosaccharide chains in the mucin-like glycoprotein component of the complex.
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PMID:GPI-anchored glycoconjugates from Trypanosoma cruzi trypomastigotes are recognized by lytic anti-alpha-galactosyl antibodies isolated from patients with chronic Chagas' disease. 808 Dec 63

Water-soluble polyacrylamide having 3'-sialyl N-acetyl-lactosamine [Neu5Ac alpha (2-->3)Gal beta (1-->4)GlcNAc] was enzymatically prepared by stepwise sugar-elongation on a water-soluble GlcNAc-bearing polyacrylamide. It was demonstrated that the flexible GlcNAc branches of the polymer chains allow quantitative galactosylation with bovine galactosyl transferase and partial sialylation by Trypanosoma cruzi trans-sialidase. Unsialylated N-acetyl-lactosamine side chains can be removed with beta-D-galactosidase and N-acetyl-beta-D-glucosaminidase to afford the targeted polymer containing 3'-sialyl N-acetyl-lactosamine.
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PMID:Chemoenzymic preparation of a glycoconjugate polymer having a sialyloligosaccharide: Neu5Ac alpha (2-->3)Gal beta (1-->4)GlcNAc. 812 20

In a previous report (Kitajima, K., Inoue, S., and Inoue, Y. (1989) Dev. Biol. 132, 544-553), we found the presence of a heavily glycosylated polyprotein, "H-hyosophorin," isolated from the unfertilized eggs of Oryzias latipes. We now report our detailed analysis of the structure of the N-glycan chain in L-hyosophorin, the smallest repeating unit of H-hyosophorin, which was isolated from the fertilized eggs of O. latipes and formed from H-hyosophorin upon fertilization. The N-glycan structures were defined by a combination of compositional analysis, methylation analysis, selective chemical degradation (i.e. mild methanolysis, periodate-Smith degradation, and hydrazinolysis-nitrous acid deamination), enzymatic (endo-beta-galactosidase, peptide:N-glycanase, and Newcastle disease virus sialidase) digestion, and instrumental analyses (one- and two-dimensional proton nuclear magnetic resonance spectroscopy and fast atom bombardment mass spectrometry) which revealed novel and unique features: (a) the presence of highly branched poly-N-acetylactosamino pentaantennary structures; (b) the presence of a beta-galactosylated Lewis X antigenic epitope, Gal beta 1-->4 Gal beta 1-->4 (Fuc alpha 1-->3) GlcNAc beta 1-->; (c) the presence of a beta-galactosylated sialyl Lewis X structure, Gal beta 1-->4 (Neu5Ac alpha 2-->3) Gal beta 1-->4(Fuc alpha 1-->3) GlcNAc beta 1-->; (d) the presence of Gal beta 1-->4 Gal beta 1--> and Gal beta 1--> 4Gal beta 1-->4Gal beta 1--> as the major and minor groupings, respectively; and (e) the presence of the branched Gal residues, -->4GlcNAc beta 1-->3(Gal beta 1-->4) Gal beta 1-->. This study represents the first detailed investigation regarding the nature of highly branched complex asparagine-linked pentaantennary glycans in glycoproteins. The unique expression of such bulky multiantennary glycan units on proteins could be essential during early embryogenesis.
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PMID:Structural studies of a novel type of pentaantennary large glycan unit in the fertilization-associated carbohydrate-rich glycopeptide isolated from the fertilized eggs of Oryzias latipes. 813 8

Several sialylated and fucosylated oligosaccharides, based upon the N-acetyllactosaminyl core structure, have been synthesized from a single trisaccharide glycoside, beta-D-GlcNAc-(1-->3)-beta-D-Gal-(1-->4)-beta-D-GlcNAc-OCH2(CH2)++ +7CO2CH3, by the sequential use of several glycosyltransferases and one sialidase. In these chemoenzymic syntheses, selective internal monofucosylation of a dimeric N-acetyl-lactosaminyl tetrasaccharide is achieved via two routes. It is demonstrated that the pentasaccharide beta-D-Gal-(1-->4)-beta-D-GlcNAc-(1-->3)-beta-D-Gal-(1-->4)-[alpha- L-Fuc-(1-->3)]-beta-D-GlcNAc-OCH2(CH2)7-CO2CH3 is an acceptor for the rat liver beta-D-Gal-(1-->3/4)-D-Glc-NAc alpha 2,3- and beta-D-Gal-(1-->4)-D-GlcNAc alpha 2,6-sialyltransferases. Among the structures obtained is the terminal hexasaccharide of the CD-65/VIM-2 epitope.
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PMID:Chemoenzymic synthesis of sialylated and fucosylated oligosaccharides having an N-acetyllactosaminyl core. 814 87

Two gangliosides were efficiently synthesized from asialo-GM1 (Gal beta 1-3GalNAc beta 1-4Gal beta 1-4Glc beta 1-1 Cer) and cytidine 5'-phosphate-N-acetylneuraminic acid (CMP-NeuAc) by using sialyltransferases in rat liver Golgi vesicles in vitro. These gangliosides were rapidly purified by a combination of anion exchange and reverse-phase column chromatographies. The ganglioside structures were determined by TLC analysis, treatment with a sialidase from Salmonella typhimurium LT2, which specifically hydrolyzes alpha 2-3 N-acetylneuraminic acid (NeuAc alpha 2-3) linkages, TLC immunostaining, and 1H-NMR spectroscopy. One of the gangliosides was identified as GD1 alpha [Neu-Ac alpha 2-3Gal beta 1-3(NeuAc alpha 2-6)GalNAc beta 1-4Gal beta 1-4Glc beta 1-1 Cer]. The other ganglioside was determined to be GM1b (NeuAc alpha 2-3Gal beta 1-3GalNAc beta 1-4Gal beta 1-4Glc beta 1-1 Cer), which has been reported in a previous study [Pohlentz, G., Klein, D., Schmitz, D., Schwarzmann, G., Peter-Katalinic, J. & Sandhoff, K. (1988) Biol. Chem. Hoppe-Seyler 369, 55-63]. Finally, GM1b and GD1 alpha were obtained from asialo-GM1 as a starting material in 8.1% and 1.2% overall yields, respectively. This study also suggests that the novel synthetic pathway asialo-GM1-->GM1b-->GD1 alpha may exist in rat liver.
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PMID:In vitro synthesis of disialoganglioside (GD1 alpha) from asialo-GM1 using sialyltransferases in rat liver Golgi vesicles. 816 48

The cDNA encoding GM2 activator was expressed in the Escherichia coli/pT7-7 system. The yield of the GM2 activator with greater than 99% purity was about 3 mg per liter culture. The recombinant GM2 activator was found to be as active as that isolated from human kidney. The availability of the recombinant GM2 activator enabled us to critically examine the specificity of this activator protein. Our results show that the specificity of GM2 activator is not as strict as that reported previously. Although GM2 activator stimulates most efficiently the degradation of GM2 carried out by beta-N-acetylhexosaminidase A (Hex A), this activator also stimulates the following reactions: (a) conversion of GM2 to GA2 by clostridial sialidase; (b) hydrolysis of GalNAc from dipalmitoylphosphatidylethanolamine-II3NeuAcGgOse3 by Hex A; and (c) liberation of Gal from GM1 by beta-galactosidase at a high activator concentration. Thus, this activator does not differentiate between GM2 and dipalmitoylphosphatidylethanolamine-II3NeuAcGgOse3 or between Hex A and clostridial sialidase. The micellar forms of GD2 and GalNAc-GD1a were found to be more readily hydrolyzed by Hex A than GM2 in the absence of GM2 activator. Our results also show that saposin B can enhance the stimulatory activity of GM2 activator, but it cannot promote the stimulatory activity of sodium taurodeoxycholate. Taken together, our results suggest that the mechanism of action of GM2 activator is different from saposin B, and the action of GM2 activator is more than to solubilize lipid substrates. The effectiveness of GM2 activator in stimulating the hydrolysis of GM2 may be due to its ability to recognize the specific trisaccharide structure of the GM2 epitope, GalNAc beta 1-->4(NeuAc alpha 2-->3)Gal-, and to modify the GalNAc-NeuAc interaction in this structure.
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PMID:Expression and specificity of human GM2 activator protein. 820 33

The asparagine-linked sugar chains of blood coagulation factor VIII purified from porcine plasma were released as oligosaccharides by hydrazinolysis. These sugar chains were converted to radioactive oligosaccharides by reduction with sodium borotritide and separated into neutral and acidic fractions by paper electrophoresis. Most of the acidic oligosaccharides were converted to neutral ones by sialidase digestion, indicating that they are sialyl derivatives. The neutral and the sialidase-treated acidic oligosaccharides were fractionated by serial chromatography on immobilized lectin columns. Structural study of each oligosaccharide by sequential exoglycosidase digestion and by methylation analysis revealed that porcine factor VIII contains high mannose-type and bi-, tri-, and tetraantennary complex-type sugar chains. Sixty-seven percent of the complex-type sugar chains contained the Gal alpha 1-->3Gal group, and 23% of the biantennary complex-type sugar chains contained the bisecting N-acetylglucosamine residue. These structures were not detected in the sugar chains of human plasma factor VIII. An in vitro competition study of von Willebrand factor and anti-Gal antibody for binding to factor VIII revealed that von Willebrand factor prevented antibody binding to Gal alpha 1-->3Gal groups in porcine factor VIII sugar chains. This suggests that anti-Gal antibody present in human plasma may not interact with the sugar chains of therapeutic porcine factor VIII. Reverse-transcription polymerase chain reaction was used to identify porcine tissues producing FVIII mRNA. These studies revealed that the kidney is one of the major tissues expressing factor VIII which may contain the sugar chains with the bisecting N-acetylglucosamine residue.
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PMID:Structural study of the sugar chains of porcine factor VIII--tissue- and species-specific glycosylation of factor VIII. 827 17


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