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)

Human lung adenocarcinoma sub-cell lines HAL-8, HAL-24 and HAL-33, showing different lung colonization potential (LCP), were established from human lung adenocarcinoma cell line KUM-LK-2 using repeated cloning with limiting dilution technique. Cell lines HAL-8 and -33 were characterized by high and low LCP, respectively, while HAL-24 did not give rise to lung colonies. The cell surface protein and carbohydrate profiles were determined by cell surface labeling (with lactoperoxidase-dependent 125I-iodination and galactose oxidase-NaB3H4, respectively) followed by SDS-gel electrophoresis. Various carbohydrate epitopes expressed at the cell surface were analysed by cytofluorometry using various monoclonal antibodies (MAbs) directed to Le(x), sialosyl-Le(x), sialosyl dimeric Le(x), T, Tn and sialosyl-Tn structures, which are often reported as being highly expressed in a variety of human cancers, particularly adenocarcinoma. Expression of sialosyl dimeric Le(x) (defined by MAb FH6) was high on HAL-8, moderate on HAL-33, and relatively low on HAL-24. In contrast, each of the three lines showed essentially equal expression (as determined by MAb reactivity) of sialosyl-Tn (defined by MAb TKH2), Le(x) (defined by MAb SH1), and Tn (defined by MAb 1E3). The cell lines showed extremely weak expression of T (defined by MAb HH8). LCP of HAL-8 and -33 was completely inhibited by sialidase treatment of cells. It is suggested that higher expression of sialosyl dimeric Le(x) (defined by MAb FH6) in HAL-8 cells may play an important role in higher potential of blood-borne lung colonization.
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PMID:Human lung adenocarcinoma cell lines with different lung colonization potential (LCP), and a correlation between expression of sialosyl dimeric Le(x) (defined by MAb FH6) and LCP. 167 53

Resident rat peritoneal macrophages express a galactose-recognizing system, which mediates binding and uptake of cells and glycoproteins exposing terminal galactose residues. Here we describe the identification, isolation, and characterization of the corresponding receptor molecule. Using photoaffinity labelling of adherent peritoneal macrophages with the 4-azido-6-125I-salicylic acid derivative of anti-freeze glycoprotein 8 followed by SDS-PAGE and autoradiography, we identified the receptor of these cells as a protein with an apparent molecular mass of 42 kDa. Furthermore, cell surface receptors were radioiodinated by an affinity-supported labelling technique using the conjugate of asialoorosomucoid and lactoperoxidase, followed by extraction and isolation by affinity chromatography. Finally, the native receptor was isolated and analysed. To estimate its binding activity in solutions, a suitable binding assay was developed, using the precipitation of receptor-ligand complex with polyethylene glycol to separate bound from unbound 125I-asialoorosomucoid, which was used as ligand. It is shown that the isolated receptor binds to galactose-exposing particles and distinguishes between sialidase-treated and -untreated erythrocytes, similar to peritoneal macrophages. The binding characteristics of the membrane-bound and the solubilized receptor are described in the following paper of Lee et al.
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PMID:The galactose-recognizing system of rat peritoneal macrophages; identification and characterization of the receptor molecule. 285 Aug 17

The adherence of Actinomyces naeslundii to human epithelial (KB) cells is mediated by the interaction of a fimbrial lectin on this oral bacterium with epithelial cell receptors exposed by sialidase. The D-galactose- and N-acetyl-D-galactosamine-reactive plant lectins from peanut and from Bauhinia purpurea inhibit this interaction. This report describes the partial purification and characterization of a 160-kilodalton (kDa) cell surface glycoprotein which is the principal receptor for these lectins. Radioiodinated lectins detected a band of 160 kDa on sialidase-treated Western blots of epithelial cell extracts but did not detect bands on nontreated filters. However, wheat germ agglutinin was reactive with the 160-kDa band on filters that were not treated with sialidase, suggesting that this lectin recognizes the sialic acid residues of this molecule. The 160-kDa component was partially purified from n-octylglucoside extracts of the epithelial cells by wheat germ agglutinin affinity chromatography. This molecule was metabolically labeled with D-[14C]glucosamine and labeled at the cell surface by lactoperoxidase-catalyzed iodination or periodate oxidation followed by sodium borotritide reduction. Incubation of epithelial cells with sialidase before extraction resulted in the loss of the 160-kDa band and the appearance of a band at 200 kDa which was directly reactive with 125I-labeled peanut agglutinin. These results indicate that the 160-kDa glycoprotein on the surface of the epithelial cell serves as a receptor for the agglutinins from the peanut and B. purpurea and presumably the fimbrial lectin of actinomyces.
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PMID:A 160-kilodalton epithelial cell surface glycoprotein recognized by plant lectins that inhibit the adherence of Actinomyces naeslundii. 287 66

High-molecular-weight polymers of alpha-1,6-linked D-glucans are insoluble in alcohol solutions. Whole, but not parotid, saliva prevented the precipitation of D-glucans by 80% (vol/vol) ethanol, showing that the whole saliva contained a factor which complexed with the glucan to render it alcohol soluble. The glucan-binding factor was retained on a column of Sephacryl S-200 which had been preequilibrated with 80% ethanol. The factor was then eluted with water. Passive hemagglutination assays revealed that the glucan-binding factor could sensitize erythrocytes to agglutination with anti-poly(glycerolphosphate), suggesting that the active glucan-binding component with lipoteichoic acid. The glucan-solubilizing factor was resistant to heat (100 degrees C), proteases, sialidase, lysozyme, lactoperoxidase, trichloroacetic acid, and Triton X-100. When sucrose was added to saliva, a suspension of Streptococcus cricetus AHT, or a suspension of Streptococcus sanguis 10556, relatively large amounts of glucan-binding factor were released in a soluble form. In addition, penicillin G caused the release of the glucan-solubilizing component from a suspension of S. cricetus AHT. It is suggested that whole saliva contains a component, tentatively identified as lipoteichoic acid, which can complex with glucans in a relatively hydrophobic solvent. This type of complex formation may be important in the adhesion of oral streptococci to saliva-coated surfaces.
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PMID:Glucan-binding factor in saliva. 316 92