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)

The asparagine-linked sugar chains of rabbit immunoglobulin G (IgG) and its Fc and Fab fragments were quantitatively liberated from the polypeptide portions by hydrazinolysis followed by N-acetylation and NaB3H4 reduction. After fractionation by paper electrophoresis, lectin chromatography, and gel filtration, their structures were studied by sequential exoglycosidase digestion in combination with methylation analysis. Rabbit IgG was shown to contain 2.3 mol of asparagine-linked sugar chains per molecule distributed in both the Fc and Fab fragments. The sugar chains were of the biantennary complex type containing four cores: Man alpha 1----6(Man alpha 1----3)(+/- GlcNAc beta 1----4)Man beta 1----4GlcNAc beta 1----4(+/- Fuc alpha 1----6)-GlcNAc. A total of 16 distinct neutral oligosaccharide structures was found after sialidase treatment. The galactose residue in the monogalactosylated oligosaccharides was present on either the alpha 1----3 or alpha 1----6 side of the trimannosyl core. The Fab fragments contained neutral, monosialylated, and disialylated oligosaccharides, whereas the Fc fragment contained only neutral and monosialylated structures. The oligosaccharides isolated from the Fab fragments also contained more galactose and bisecting N-acetylglucosamine residues than those from the Fc fragments.
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PMID:Structures of the sugar chains of rabbit immunoglobulin G: occurrence of asparagine-linked sugar chains in Fab fragment. 407 13

The carbohydrate structures of two membrane glycoproteins (HANA protein and F protein) of HVJ have been determined on materials purified from virions grown in the allantoic sac of embryonated chicken eggs. Both glycoproteins contain fucose, mannose, galactose, and glucosamine but not galactosamine, indicating that their sugar chains are exclusively of the asparagine-linked type. The radioactive oligosaccharide fractions obtained from the two glycoproteins by hydrazinolysis followed by NaB[3H]4 reduction gave quite distinct fractionation patterns after paper electrophoresis. More than 75% of the oligosaccharides from F protein were acidic and separated into at least four components by paper electrophoresis. Only 18% of the oligosaccharide from HANA protein was an acidic single component. These acidic oligosaccharides could not be converted to neutral oligosaccharides by sialidase digestion. Structural studies of the neutral oligosaccharide fractions from HANA and F proteins revealed that both of them are mixtures of a series of high mannose type oligosaccharides and of complex type oligosaccharides with Gal beta 1 leads to (Fuc alpha 1 leads to 3) GlcNAc group in their outer chain moieties.
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PMID:Carbohydrate structures of HVJ (Sendai virus) glycoproteins. 626 75

Newcastle disease virus sialidase was found to exhibit strict specificity for hydrolysis of the NeuAc alpha 2 leads to 3Gal linkage contained in glycoprotein oligosaccharides both N-linked to asparagine and O-linked to threonine or serine under conditions that left oligosaccharides containing the NeuAc alpha 2 leads to 2 leads to 6Gal and NeuAc alpha 2 leads to 6GallNAc linkages intact. This was determined, in part, by examining the viral sialidase for its ability to hydrolyze glycoprotein oligosaccharides derivatized with purified sialyltransferases to contain the [14C]NeuAc alpha 2 leads to 3Gal, [14C]NeuAc alpha 2 leads to 6GalNAc, and [14C]NeuAc alpha 2 leads to 6Gal linkages. The viral sialidase was also tested for hydrolysis of the NeuAc alpha 2 leads to 3Gal and NeuAc alpha 2 leads to 6Gal linkages on the N-linked oligosaccharides of alpha 1-acid glycoprotein. Selective hydrolysis of the NeuAc alpha 2 leads to 3Gal linkage was shown by periodate oxidation and by 500-MHz 1H-NMR spectroscopy of native and sialidase-treated glycopeptides. The NMR spectra, together with composition data, further indicated that the NeuAc alpha 2 leads to 3Gal and NeuAc alpha 2 leads to 6Gal linkages were localized to specific branches of the major tri- and tetraantennary oligosaccharides of alpha 1-acid glycoprotein. The results indicate that the Newcastle disease virus sialidase can initiate the selective degradation of N-linked oligosaccharide branches containing the NeuAc alpha 2 leads to 3Gal linkage.
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PMID:Newcastle disease virus contains a linkage-specific glycoprotein sialidase. Application to the localization of sialic acid residues in N-linked oligosaccharides of alpha 1-acid glycoprotein. 629 Apr 80

Asialo-oligosaccharides obtained by sialidase digestion of asparagine-linked acidic sugar chains of promyelocytic leukemic cells (HL-60) differed in size distribution from those of cells induced to undergo myeloid or monocytoid differentiation. High-molecular-weight oligosaccharides which are predominant in HL-60 cells, decreased slightly during myeloid differentiation and markedly during monocytoid differentiation with concomitant increase of biantennary oligosaccharides. Structural analyses revealed that the induced monocytoid cells contain a series of complex-type oligosaccharides with bi-, tri-, and tetraantennary structures and high-molecular-weight oligosaccharides with N-acetyllactosamine repeating units, which show diversity in the presence or absence of the fucose residue linked to the reducing terminal N-acetylglucosamine, of the bisecting N-acetylglucosamine residue, and of the X-antigenic determinant in their outer chain moieties. Methylation analysis of each class of oligosaccharides of HL-60 cells and of their differentiated counterparts revealed the presence of similar heterogeneity in their structures, indicating that the difference is only quantitative. The results show that the shifts in size of the oligosaccharides found in the differentiated cells are derived from changes in outer chain formation and elongation of N-acetyllactosamine repeating units, and thus suggests that the decreased expression of N-acetylglucosaminyltransferases may be involved especially in the monocytoid differentiation program.
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PMID:Changes in asparagine-linked sugar chains of human promyelocytic leukemic cells (HL-60) during monocytoid differentiation and myeloid differentiation. Decrease of high-molecular-weight oligosaccharides in acidic fraction. 643 33

The sialic acid residues were removed from asparagine-linked sugar chains on the C-terminal non-collagenous globular regions of human C1q by sialidase digestion. Both the haemolytic activity and the binding ability to immunoglobulin G (IgG) (Fc-binding ability) of C1q were unimpaired, even after the complete removal of sialic acid from these sugar chains. On the other hand, the rate of disappearance of C1q from the circulation was greatly accelerated by its desialylation, that is, the radioactivity of the infused intact and desialylated C1q was reduced to half for 200 min and for 140 min in the circulation of rats, respectively. A mixture of entire asparagine-linked sugar chains consisting of neutral, monosialyl and disialyl oligosaccharides was isolated from the intact C1q molecule by hydrazinolysis. The oligosaccharide-mixture isolated, after NaBH4 reduction, was added to assay system of C1q, but neither the haemolytic activity nor the Fc-binding ability was influenced.
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PMID:A study of the role of the asparagine-linked sugar chains of human complement subcomponent C1q in its biological activities. 660 59

Human lactoferrin contains 2 asparagine-linked sugar chains in 1 molecule. These sugar chains were released as oligosaccharides by hydrazinolysis from two lactoferrin samples of different races. The two oligosaccharide fractions gave exactly the same fractionation pattern upon paper electrophoresis and Bio-Gel P-4 column chromatography after sialidase digestion. A structural study of the oligosaccharides obtained from the two samples by sequential exoglycosidase digestion in combination with methylation analysis also gave the same results indicating that there is no racial difference both in quality and quantity of the sugar chain moiety of lactoferrin. In addition to the two acidic sugar chains, NeuAc alpha 2 leads to 6Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6(NeuAc alpha 2 leads to 6Gal beta 1 leads 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4(Fuc alpha 1 leads to 6)GlucNAc and Gal beta 1 leads to 4(Fuc alpha 1 leads to 3)GlcNAc beta 1 leads to 1Man alpha 1 leads to 6(NeuAc alpha 2 leads to 6Gal beta 1 leads 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4(Fuc alpha 1 leads to 6)GlcNAc, and two novel acidic sugar chains, Gal beta 1 leads to 4(Fuc alpha 1 leads to 3)GlcNAc beta 1 leads to Man alpha 1 leads to 6(NeuAc alpha 2 leads to 6Gal beta 1 leads to 4GlcNAc beta 1 leads to 3Gal beta 1 leads to 4GlcNAc beta 1 leads to 2 Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4(Fuc alpha 1 leads to 6(GlcNAc and Gal beta 1 leads to 4(Fuc alpha 1 leads to 3)GlcNAc beta 1 leads to 3Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 6(NeuAc alpha 2 leads to 6Gal beta 1 leads to 4GlcNAc beta 1 leads to 2Man alpha 1 leads to 3)Man beta 1 leads to 4GlcNAc beta 1 leads to 4(Fuc alpha 1 leads to 6)GlcNAc, were found to occur in human lactoferrin.
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PMID:Structural study of the sugar chains of human lactoferrin: finding of four novel complex-type asparagine-linked sugar chains. 706 58

Human prothrombin contains three asparagine-linked sugar chains in one molecule. The sugar chains were quantitatively liberated as radioactive oligosaccharides from the polypeptide moiety by hydrazinolysis followed by N-acetylation and Nab3H4 reduction. All of the oligosaccharides contain N-acetylneuraminic acid. The neutral oligosaccharides obtained from all acidic oligosaccharides by sialidase digestion are identical. By the combination of sequential exoglycosidase digestion and methylation analysis, the structures of the asparagine-linked sugar chains of human prothrombin were confirmed to be as follows: (sequence in text).
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PMID:Studies on the structures of the carbohydrate moiety of human prothrombin. 730 9

The plasma membrane glycoproteins of calf thymocytes were converted to glycopeptides by exhaustive pronase digestion. Glycopeptides with asparagine-linked sugar chains were separated from those with mucine-type sugar chains by Bio-Gel P-10 column chromatography. The asparagine-linked sugar chains were released as oligosaccharides from the peptide moiety by hydrazinolysis and labeled by reduction with NaB[3H]4. The radioactive oligosaccharides were fractionated into fifteen acidic components and ten neutral components by combination of paper electrophoresis and Bio-Gel P-4 column chromatography. The acidic nature of all fifteen acidic components can be ascribed to their N-acetylneuraminic acid residues. The Bio-Gel P-4 column chromatographic patterns of the neutral oligosaccharide fraction and of the neutral fraction obtained on sialidase treatment of the pooled acidic oligosaccharide fraction were totally different, indicating that the acidic oligosaccharides are not simple sialyl derivatives of the neutral oligosaccharides.
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PMID:Asparagine-linked sugar chains of glycoproteins in calf thymocyte plasma membrane. Isolation and fractionation of oligosaccharides liberated by hydrazinolysis. 741 Mar 36

CD36 is a glycoprotein included in the bovine milk fat globule membrane derived from mammary secretory epithelial cells during lactation. Asparagine-linked sugar chains were quantitatively released from CD36 as oligosaccharides by hydrazinolysis. These sugar chains were converted to radioactive oligosaccharides by reduction with NaB3H4 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 sialidase-treated acidic oligosaccharides were fractionated by Bio-Gel P-4 column chromatography in combination with serial chromatography on immobilized lectin columns including a Wistaria floribunda agglutinin (WFA)-agarose column. WFA is known to bind oligosaccharides terminating with either an alpha- or beta-N-acetylgalactosamine residue. Structural studies of oligosaccharides in each fraction by sequential exoglycosidase digestion as well as methylation analysis revealed that CD36 contains high mannose-type, hybrid-type, and bi, tri-, and tetraantennary complex-type sugar chains. A portion of the hybrid-type and the complex-type sugar chains which bound to a WFA-agarose column (28% of all oligosaccharides) contained the GalNAc beta 1-->4GlcNAc group(s) instead of the Gal beta 1-->4GlcNAc group(s) in their outer chain moieties. Like oligosaccharides found in human luteinizing hormone [Weisshaar, G., Hiyama, J., Renwick, A. G., & Nimtz, M. (1991) Eur. J. Biochem. 195, 257-268], some of the GalNAc beta 1-->4GlcNAc groups found in the CD36 oligosaccharides were sialylated as the Neu5Ac alpha 2-->6GalNAc group. Furthermore, most of the hybrid-type sugar chains of CD36 with the Gal/GalNAc beta 1-->4GlcNAc beta 1-->2 outer chain on their Man alpha 1-->3 arm contained an unusual Man alpha 1-->2Man alpha 1-->3 group on their Man alpha 1-->6 arm.
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PMID:Structural study of the sugar chains of CD36 purified from bovine mammary epithelial cells: occurrence of novel hybrid-type sugar chains containing the Neu5Ac alpha 2-->6GalNAc beta 1-->4GlcNAc and the Man alpha 1-->2Man alpha 1-->3Man alpha 1-->6Man groups. 768 47

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


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