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)

A lectin-like substance was isolated and purified from bovine spleen. This protein was named bovine spleen binding protein (BSBP). BSBP has binding activity for sialidase-treated bovine erythrocytes but not for normal erythrocytes. It specifically recognizes terminal galactose residues of sugar moieties of the bovine erythrocyte cell surface. BSBP shows an apparent molecular weight of 240,000. It is an acidic protein having a pI value of 4.8 and containing 13% carbohydrates. It has mitogenic activity against human peripheral lymphocytes. The physiological role of BSBP has not been clarified yet, but it may play a significant role in the clearance of aged erythrocytes which have a decreased amount of sialic acid on the cell surface.
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PMID:A lectin-like substance from bovine spleen. 54 63

The binding to normal and sialidase-treated human erythrocytes and lymphocytes of four 125I-labeled lectins [Maackia amurensis hemagglutinins (MAM and MAH), Ricinus communis hemagglutinin (RCH), and Bauhinia purpurea hemagglutinin (BPH)] was studied in detail. The quantitative inhibition assays against the lectin binding to the cells were also performed with various glyco-proteins and glycopeptides as inhibitors. The comparison of the inhibition constants of the inhibitors thus obtained with the association constants of the lectins to the cells permitted estimation of the relative receptor activities of cell surface glyco-proteins toward the lectins.
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PMID:Elucidation of lectin receptors by quantitative inhibition of lectin binding to human erythrocytes and lymphocytes. 97 78

Combined models of cytokine-induced inflammation in the skin and spinal cord of the rat were utilised to demonstrate in vivo that circulating lymphocytes depend upon sialylated adhesion molecules on their surface for maximal recruitment into inflammatory sites in both tissues. When radiolabelled normal spleen cells were incubated with sialidase from Vibrio cholerae or Clostridium perfringens, or with the specific sialic acid-binding lectin from Limax flavus, prior to being washed and injected intravenously into rats, they accumulated significantly less than untreated control cells into tumor necrosis factor (TNF)-activated spinal cord and skin. Pretreatment of splenocytes with sialidase plus the competitive inhibitor 2,3-dehydro-2-deoxy-N-acetylneuraminic acid (DDN) partially restored the accumulation of radiolabelled cells at both inflammatory sites, providing evidence for the specificity of sialidase treatment and the importance of sialyl residues. Pretreatment of macrophage-depleted spleen lymphocytes, or ovalbumin-specific W3/25+ (CD4) cell line T lymphocytes with sialidase produced similar decrements in accumulation at inflammatory sites, demonstrating that lymphocytes, including memory T cells, were relying on sialyl ligands for maximal recruitment. Results from this in vivo study are interpreted as providing indirect evidence that inducible sialyl-binding molecules, probably of the 'selectin' type, occur to a functionally significant extent on activated central nervous system (CNS) endothelium. We speculate that such carbohydrate-binding adhesion molecules may play an important role in the recruitment of inflammatory cells during the formation of CNS lesions in diseases such as the encephalomyelitides and multiple sclerosis.
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PMID:Sialyl ligands facilitate lymphocyte accumulation during inflammation of the central nervous system. 128 23

The specificity of the anti A+N lectin of Moluccella laevis (MLL) was examined by hemagglutination experiments with enzyme-modified human erythrocytes and by inhibition of hemagglutination. In addition, binding to various glycoproteins and inhibition by different sugars and glycoproteins were examined by enzyme immunoassay with antibodies to the lectin. Treatment of AMM erythrocytes with proteolytic enzymes increased their agglutinability by MLL 4-16-fold; similar treatment of ONN cells decreased their agglutinability 8-16-fold. This is in line with the known location and enzyme sensitivity of A and N specificity determinants. Treatment of the erythrocytes with sialidase increased their agglutinability and abolished the distinction between N and M cells. Hapten inhibition of hemagglutination of AMM and ONN erythrocytes by the lectin, and its binding to glycoproteins measured by enzyme immunoassay, confirmed the high specificity of MLL for N-acetyl-D-galactosamine (200-500 times more than for D-galactose) and suggested the presence of hydrophobic interactions around HO-2 of the D-galactose unit. The methyl alpha-glycosides of D-galactose and of N-acetyl-D-galactosamine were better inhibitors than the corresponding beta-glycosides; this preference was abolished, and sometimes reversed, when the p-nitrophenyl glycosides of the same monosaccharides were tested, stressing again the importance of hydrophobic interactions in the binding of carbohydrates to MLL. The lectin reacted well with ONN substance and with glycophorin A of the N phenotype (GPAN), but did not react with OMM substance or GPAM. The strongest inhibitor was asialo ovine submaxillary mucin, which contains many unsubstituted alpha-D-GalpNAc-(1-->3)-Ser/Thr residues; calculated per N-acetyl-D-galactosamine residue, it was 1500 stronger than free N-acetyl-D-galactosamine. In accordance with this result, it was found that the lectin strongly agglutinates Tn cells. The specificity of MLL can, thus, be defined as anti-Tn, crossreactive with blood types A and N, and with sialosyl-Tn. The N-specificity can best be explained by assuming that GPAN contains a small number of unsubstituted or partially sialylated alpha-D-GalpNAc-(1-->3)-Ser/Thr residues, which are present in smaller proportions, if at all, in GPAM.
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PMID:Immunochemical studies on the combining site of the A + N blood type specific Moluccella laevis lectin. 129 Oct 50

The N-acetyl-9-O-acetylneuraminic acid-alpha-p-aminophenylthioketoside 7 was synthesized as a sialidase-stable ligand for the affinity chromatography of a lectin with preferential affinity to O-acetylated sialic acids. The thioketoside was prepared by phase-transfer-catalysed glycosidation followed by Zemplen deacetylation. Regioselective acetylation of the completely de-O-acetylated derivative was practised by two different methods. The acetylation with trimethylorthoacetate did not show the desired selectivity for hydroxyl groups; in addition to the acetylation in position 9 extensive formation of an acetimidate ester derivative with the amino-group in the aminophenyl-moiety was observed. However the esterification with N,N-dimethylacetamide dimethyl acetal resulted in an exclusive acetylation of the hydroxyl-group in position 9. After catalytic hydrogenation this ligand was immobilized both directly and by a six-carbon long spacer group to the agarose matrix. The adsorbents were applied in the affinity chromatography of the lectin and their binding capacity and selectivity compared to those of the formerly used mucin matrix. In both respects the thioketoside coupled by the spacer turned out to be a better ligand for the isolation of the lectin than the mucin.
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PMID:Synthesis of N-acetyl-9-O-acetylneuraminic acid alpha-p-amino-phenylthioketoside and its application as ligand in the affinity chromatography of a lectin with preferential affinity to O-acetylated sialic acids. 129 10

The cDNA coding for pre-peanut agglutinin (PNA) was isolated from a bacterial expression library. It codes for a polypeptide of 273 amino acids composed of a hydrophobic signal peptide of 23 amino acids and a mature protein of 250 amino acids. The sequence of the latter is identical to that of native PNA, determined very recently by conventional methods, except that it contains 14 additional amino acids at the C-terminus. Bacterial cells harboring a plasmid with the prePNA-cDNA, produced two PNA cross-reacting proteins: one migrated on SDS-PAGE identically with the native lectin (apparent mol. wt. 31 kDa); the other, at 35 kDa, was a beta-galactosidase pre-PNA fusion protein. The former protein possessed an N-terminal sequence identical to that of the mature, native PNA, suggesting that it was processed from the 35 kDa prePNA precursor. Only the 31 kDa protein was exported into the bacterial periplasmic space, and had the ability to bind to galactose-Sepharose. The isolated processed protein had the same hemagglutinating activity as the native lectin, when assayed with sialidase-treated human erythrocytes. Like the native lectin, it did not agglutinate the untreated cells, was not inhibited by N-acetylgalactosamine, and was inhibited by Gal beta 1----3GalNAc 30-times more strongly than by galactose.
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PMID:Cloning, sequence analysis and expression in Escherichia coli of the cDNA encoding a precursor of peanut agglutinin. 133 58

P-selectin (CD62, GMP-140, PADGEM), a Ca(2+)-dependent lectin on activated platelets and endothelium, functions as a receptor for myeloid cells by interacting with sialylated, fucosylated lactosaminoglycans. P-selectin binds to a limited number of protease-sensitive sites on myeloid cells, but the protein(s) that carry the glycans recognized by P-selectin are unknown. Blotting of neutrophil or HL-60 cell membrane extracts with [125I]P-selectin and affinity chromatography of [3H]glucosamine-labeled HL-60 cell extracts were used to identify P-selectin ligands. A major ligand was identified with an approximately 250,000 M(r) under nonreducing conditions and approximately 120,000 under reducing conditions. Binding of P-selectin to the ligand was Ca2+ dependent and was blocked by mAbs to P-selectin. Brief sialidase digestion of the ligand increased its apparent molecular weight; however, prolonged digestion abolished binding of P-selectin. Peptide:N-glycosidase F treatment reduced the apparent molecular weight of the ligand by approximately 3,000 but did not affect P-selectin binding. Western blot and immunodepletion experiments indicated that the ligand was not lamp-1, lamp-2, or L-selectin, which carry sialyl Le(x), nor was it leukosialin, a heavily sialylated glycoprotein of similar molecular weight. The preferential interaction of the ligand with P-selectin suggests that it may play a role in adhesion of myeloid cells to activated platelets and endothelial cells.
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PMID:Identification of a specific glycoprotein ligand for P-selectin (CD62) on myeloid cells. 137 49

P-selectin (CD62) is a Ca(2+)-dependent lectin expressed on activated platelets and endothelium. Although P-selectin is known to function as a receptor for myeloid cells, previous studies indicated that P-selectin also bound to a subset of lymphocytes. Using a multi-color immunofluorescence assay we found that purified P-selectin bound to 12.2 +/- 4.1% of peripheral blood lymphocytes and that P-selectin could mediate adhesion of activated platelets to lymphocytes. A subpopulation of CD4+, CD8+, and CD16+ lymphocytes bound P-selectin. There was a marked preference for P-selectin binding to memory cells (CD45RO+) in both the CD4+ and CD8+ populations. Binding to all cell types was Ca(2+)-dependent and blocked by pretreatment of the cells with sialidase. These data suggest that P-selectin may play a role in the recruitment of specific lymphocyte populations to sites of inflammation.
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PMID:P-selectin (CD62) binds to subpopulations of human memory T lymphocytes and natural killer cells. 137 21

Sugar specific lectins (PNA, RCA I, LPA, SBA, DBA, GSA IB4, GSA II, WGA, LTA, UEA I, Con A, LCA) with and without prior selective glycosidase digestion (sialidase, alpha-fucosidase, alpha-mannosidase, beta-N-acetylglucosaminidase, alpha- and beta-galactosidase, beta-glucosidase) were used in order to investigate the distribution of native accessible carbohydrates and obtain information dealing with the composition of terminal disaccharides within glycoconjugates present in acinar compartments and ductal segments of mammalian (mouse, rat, hare, and rabbit) parotid glands. Glycoconjugates containing variable amounts of mannose, glucose, N-acetylgalactosamine and N-acetylglucosamine were present in the parotid glands of all species. However, these carbohydrate chains exhibited a different composition of terminal sequences within each type of gland. For example, sialylated components having the terminal dimers sialic acid-galactose and sialic acid-N-acetylgalactosamine were found in all acinar cells, whereas fucoglycoconjugates with terminal disaccharide fucose-galactose were localized in the rat striated ducts and hare acinar cells. The terminal sequence alpha-galactose-beta-galactose was demonstrated in the mouse acinar cells. Finally, glycoconjugates characterized by the terminal dimer beta-galactose-N-acetylgalactosamine were demonstrated in the mouse acinar and ductal cells and the rat ductal ones. Thus, present findings outlined and further confirmed the possibility to elucidate the oligosaccharide structure in situ using lectin histochemistry combined with enzymatic degradation.
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PMID:Glycoconjugate composition of mammalian parotid glands elucidated in situ by lectins and glycosidases. 137 7

L-Selectin is a lectin-like receptor on lymphocytes which mediates their attachment to high endothelial venules (HEV) within lymph nodes. Previous work has identified HEV-associated endothelial ligands for L-selectin as sialylated, fucosylated and sulphated glycoproteins of approximately 50 kDa and approximately 90 kDa (Sgp50 and Sgp90). The interaction of L-selectin with these ligands is carbohydrate directed, reflecting the involvement of its amino-terminal, calcium-type lectin domain. It has been reported, and we have confirmed, that anti-Ly22 blocks the adhesive function of L-selectin without reducing its binding to a carbohydrate- based ligand PPME (phosphomannan monoester core from Hansenula hostii). The epitope for this monoclonal antibody depends on the epidermal growth factor (EGF) domain of L-selectin. We demonstrate that anti-Ly22 inhibits the interaction of L-selectin with both of the Sgps, thus establishing that the interaction of L-selectin with HEV can be accounted for by the Sgps. Furthermore, the interaction of trypsin fragments of Sgp50 with L-selectin is inhibitable both by an antibody that maps to the lectin domain and by anti-Ly22. These findings raise the possibility that anti-Ly22 is affecting the function of the lectin domain of L-selectin rather than directly antagonizing the EGF domain. Toward a further characterization of L-selectin's carbohydrate specificity, we show that Sgp50 is partially inactivated by the linkage-specific Newcastle Disease virus sialidase (alpha 2,3 linkage). We additionally demonstrate that a sialyl Lewis x-related tetrasaccharide can interact with L-selectin, as has also been demonstrated for E-selectin and P-selectin.
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PMID:Further characterization of the interaction between L-selectin and its endothelial ligands. 138 20


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