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)

The effect of alpha-galactosidase, purified from Clostridium sporogenes (Maebashi), was examined on erythrocytes from rats, rabbits and gibbons. The amount of galactose released by alpha-galactosidase from Cl. sporogenes and from coffee beans was compared. The amount of sialic acid released by Vibrio cholera sialidase was also determined. Loss of blood group B specificity following treatment with alpha-galactosidase was demonstrated with anti-B lectin. In animal models, removal of all the alpha-galactosyl residues with the coffee bean or clostridial alpha-galactosidase resulted in no change in the sequestration pattern of the treated erythrocytes over a period of several days. In contrast, erythrocytes treated with sialidase were rapidly sequestered from the circulation.
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PMID:Action of alpha-galactosidase from Clostridium sporogenes and coffee beans on blood group B antigen of erythrocytes. The effect on the viability of erythrocytes in circulation. 630 53

In contrast to other viral glycoproteins, the herpes simplex virus (HSV) glycoprotein C(gC) binds to the N-acetylgalactosamine-specific Helix pomatia lectin (HPA). In the present paper gC was purified by affinity chromatography with monospecific antibodies and the purified glycoprotein was subjected to protease digestion. HPA-binding protease-resistant glycopeptides were isolated by lectin affinity chromatography. The isolated structures did not bind to concanavalin A and seemed to lack charged groups as determined by ion-exchange chromatography. In gel filtration, the glycopeptides appeared in two peaks with molecular weights higher than 4000. The HPA-binding structures of gC were synthesized in the presence of tunicamycin, indicating that they belong to the O-glycosyl class of oligosaccharides. In addition to HPA-binding oligosaccharides, synthesis of tunicamycin-resistant wheat germ lectin-binding gC oligosaccharides was demonstrable. These were sensitive to sialidase and apparently unrelated to the HPA-binding oligosaccharides.
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PMID:Glycoprotein C of herpes simplex virus type 1: characterization of O-linked oligosaccharides. 631 56

Previous studies using the lectin RCA-I from Ricinus communis have indicated that several lysosomal enzymes in the fibroblasts of patients deficient in beta-galactosidase carry excess terminal galactose. Electrophoretic studies have shown that the same enzymes and the non-lysosomal adenosine deaminase also show excess terminal sialic acid in patients deficient in sialidase. In this paper we confirm, using Jack-bean beta-galactosidase, that the binding to RCA-I of the purified N-acetyl-beta-D-hexosaminidase from a patient with GM1 gangliosidosis depends on a terminal beta-linked galactose. We provide evidence, using bacterial sialidase and measuring the binding to RCA-I, for excess subterminal galactose on the enzymes of patients deficient in sialidase. We also show that adenosine deaminase from the fibroblasts of patients deficient in beta-galactosidase has increased binding to RCA-I. These observations suggest that in healthy individuals the carbohydrate structure of the precursors of lysosomal enzymes and possibly some other glycoproteins also includes extended carbohydrate side chains with terminal sialic acid and subterminal galactose, and that the mature enzyme extracted from tissues is the product of degradation.
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PMID:The role of lysosomal sialidase and beta-galactosidase in processing the complex carbohydrate chains on lysosomal enzymes and possibly other glycoproteins. 643 95

ABH isoantigen of 154 superficial urothelial tumor including 11 carcinoma in situ of the bladder (CIS) was investigated by the avidin-biotin-peroxidase complex (ABC) method, and the results were compared with those obtained by the specific red cell adherence (SRCA) test. T (Thomsen-Friedenreich) antigen, a precursor of other blood group antigen than ABC, was also investigated by ABC method. ABH antigen detected by ABC method seemed to be correlated to tumor grade and recurrence rate, while that by SRCA method did not. Sixty two percent of the low grade papillary bladder tumor of blood group other than O was positive by ABC method. As for the recurrence rate of low grade tumor, 11 of 33 cases (33%) with positive ABH isoantigen showed recurrence, while 13 of 21 cases (62%) without ABH isoantigen did so. In CIS, ABH antigen was deleted in 82 percent using ABC method. ABC method is more sensitive and more specific than SRCA, and the sensitivity was increased in blood O. T antigen, which is expressed in many carcinomas, (defined T(+) by Coon) is usually not detected in normal epithelium. Normally, T antigen is cryptic but can be unmasked with sialidase (cryptic T(+)). The cells which lacked T even after sialidase treatment are called cryptic T(-). We investigated T antigen expression in CIS lesion and ureteropelvic tumor by using T specific lectin (peanut agglutinin). In nine cases of CIS which ABH was negative, cryptic T(+), T(+) and cryptic T(-) were found in three, one and five cases, respectively. In ten cases of high grade ureteropelvic tumor, which ABH was all negative, cryptic T(+) was found in five cases. Of these five cases, three are well over five years after surgery. These data, although preliminary, indicate that, by combining two markers (ABH and T antigen), prognosis of urothelial tumor may be predicted better.
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PMID:[The study of ABH isoantigen and T (Thomsen-Friedenreich) antigen of superficial urothelial tumor]. 653 Feb 8

gpL115 is a lymphocyte surface component that is deficient in patients with the X-chromosome-linked immune deficiency Wiskott-Aldrich syndrome (6). The glycoprotein nature of gpL115 is demonstrated through labeling in carbohydrate moieties by [3H]NaBH4 and its synthesis by lymphocytes through labeling with [35S]methionine. Native gpL115 adheres to wheat germ lectin-Sepharose and sialidase-treated gpL115 does not adhere, indicating that native gpL115 adheres via clusters of sialic acid residues. When tested on peanut lectin, which shows specificity for the disaccharide Gal beta 1-3GalNAc, gpL115 is nonadherent and sialidase-treated gpL115 is adherent, indicating the presence of the sequence sialic acid-Gal beta 1-3GalNAc, which is characteristic for O-linked (mucin-type, acidic-type) carbohydrates. A surface glycoprotein with all the above characteristics was found on the lymphoblastoid cell line CEM. CEM cells were used as immunogen to generate the monoclonal antibody L10, an IgG1, which binds native and sialidase-treated gpL115 . Sialidase-treatment of gpL115 significantly alters its physical properties, reducing its electrophoretic mobility and changing its behavior on isoelectrofocusing. Cumulatively, these findings indicate that gpL115 , like glycophorin of erythrocytes and GPIb of platelets, is a sialoglyco protein with significant quantities of O-linked carbohydrate. On treatment with limiting sialidase concentrations, gpL115 of normal lymphocytes is transformed into a series of partially desialylated species of decreasing electrophoretic mobility. This finding resembles the situation with lymphocytes of some Wiskott-Aldrich syndrome patients. Lymphocytes of eight Wiskott-Aldrich syndrome patients were found to be deficient in 125I-labeled gpL115 . Lymphocytes from three of these patients displayed an abnormal 125I-component of apparent mol wt 135,000.
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PMID:Characterization of a human lymphocyte surface sialoglycoprotein that is defective in Wiskott-Aldrich syndrome. 654 60

Significant in vivo stimulation of granulopoiesis was induced in mice by the administration of an extract from the urine of patients with aplastic anemia (AA). Sialic acid has been identified as an important molecular component for the in vivo biological activity of this granulopoietic factor, "granulopoietin," which is distinct and different from endotoxin. Urine from patients with AA was successively fractionated by Sephadex G-50 and DEAE-cellulose chromatography. The resultant extract, which we refer to as AA urinary extract, contained approximately equal to 44 international units of erythropoietin per A unit of protein and induced 15,000 colonies of granulocyte/macrophage precursor cells (granulocyte/macrophage colony-forming units, CFU-gm) per A unit of protein with mouse bone marrow. Eight daily intraperitoneal injections of this extract in mice induced a 6.2-fold increase in peripheral blood granulocytes and a 14.6-fold increase of splenic CFU-gm, with concomitant increases in the proliferation rates of CFU-gm in both bone marrow and spleen. Pretreatment of the AA urinary extract with sialidase significantly diminished these granulopoietic effects in vivo (P less than 0.001). In contrast, both extracts (i.e., native AA and sialidase-treated AA urinary extracts) revealed high granulocyte/macrophage colony-stimulating factor activity in vitro when clonal assays were performed with mouse bone marrow. Increased in vivo and in vitro granulopoietic activities were found in the concanavalin A "break-through" fraction, indicating that these activities were due to protein(s) that did not bind to the lectin. These results reveal that this urinary extract from patients with AA is capable of inducing significant granulopoiesis in mice and that sialic acid is an important component in the maintenance of this granulopoietic effect in vivo but not in vitro.
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PMID:In vivo stimulation of murine granulopoiesis by human urinary extract from patients with aplastic anemia. 657 18

The extent and the specificity of the initial cell attachment induced by various proteins coated on plastic surfaces have been studied with the following results: (a) Cell adhesion on the surfaces coated with sialidase and beta-galactosidase was as strong as on concanavalin A and limulus lectin-coated surfaces and the reactions were strongly inhibited by glycosidase inhibitors or by competitive substrates. The adhesion on sialidase was inhibited by 2-deoxy-2,3-dehydro-N-acetylneuraminic acid and by polysialoganglioside (GT1b) at low concentration (0.05-0.1 mM). The cell adhesion on beta-galactosidase coat was inhibited by 1,4-D-galactonolactone and beta-methylgalactoside but not by alpha-methylgalactoside. Thus, the initiation of cell adhesion on glycosidase surfaces could be mediated through the interactions of the specific binding sites of the enzyme surface with the cell surface substrates under physiological conditions. (b) Cell adhesion on various lectins could be blocked by various competing monosaccharides at the concentrations similar to the inhibitory concentrations for binding of lectins from solution to the cells. (c) Cell adhesion on fibronectin surfaces as well as on gelatin-coated surfaces was equally inhibited by GT1b at relatively high concentrations (0.25-0.5 mM). Lower concentrations of GT1b (0.05-0.1 mM) inhibited the cell adhesion on surfaces of Limulus lectin and sialidase. It is suggested that the cell adhesion mediated by fibronectin is based on yet unknown interactions in contrast to a specific cell adhesion through glycosidases and lectins.
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PMID:Studies on cell adhesion and recognition. I. Extent and specificity of cell adhesion triggered by carbohydrate-reactive proteins (glycosidases and lectins) and by fibronectin. 678 7

Trypanosoma cruzi at various stages of maturation and differentiation have been isolated by conventional cellular fractionation procedures and characterized by cell surface markers using 30 highly purified lectins encompassing all known sugar specificities. Cell surface carbohydrates of the various T. cruzi stages were analyzed by agglutination and lectin-binding assays. Specific receptors for wheat germ agglutinin (WGA), Helix pomatia, Sophora japonica, and Bandeiraea simplicifolia lectin II were found only in culture epimastigotes, whereas peanut agglutinin (PNA) sites were present exclusively in amastigotes, those for Phaseolus vulgaris in bloodstream trypomastigotes and amastigotes, and for Wistaria floribunda hemagglutinin predominantly in culture forms of T. cruzi. The N-acetylgalactosamine (DGalNAc)-binding lectin from Bauhinia purpurea agglutinated and inhibited the movement of epimastigotes and bloodstream trypomastigotes, but it only inhibited--without agglutinating--culture trypomastigotes. Because both the agglutination and inhibition of movement were reversed by specific sugar haptens, Bauhinia purpurea sites were present in all the flagellated parasites. On the other hand, PNA sites were detectable on epimastigotes after the cells were treated with sialidase, whereas, at the same time, WGA receptors were completely removed and those for the other sialic acid-binding proteins, Aaptos papillata lectin II and Limulus polyphemus, were partially eliminated; moreover, the activity of Wistaria floribunda hemagglutinin, a DGalNAc-binding lectin, increased 4,000 times. Trypsinization and lyzozyme treatment of epimastigote cells did not significantly affect lectin agglutination or lectin binding. WGA reacted solely with sialic acid residues on epimastigote cell surface with an apparent association constant of 2 x 10(6) M-1, each epimastigote having an estimated average of 3 x 10(6) WGA sites, as determined by binding experiments and a minimum of 7.7 x 10(6) sialic acid residues, as calculated by colorimetric method after sialidase digestion. Evidences are presented that the sialyl residues are rapidly regenerated (in approximately 4 h) and that they, at least for the most part, are not adsorbed from the culture medium. The receptor for the D-mannose-binding lectins (concanavalin A [Con A] and Lens culinaris) must either be on the same carbohydrate moiety having the WGA site, or, if in a distinct molecule, both carrier molecules of Con A and WGA sites must be located close to each other in the plasma membrane of the parasite.
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PMID:Lectin receptors as markers for Trypanosoma cruzi. Developmental stages and a study of the interaction of wheat germ agglutinin with sialic acid residues on epimastigote cells. 700 Sep 67

Hexosaminidase C (2-acetamido-2-deoxy-beta-D-glucoside acetamidodeoxyglucohydrolase, EC 3.2.1.30) was partially purified from bovine brain tissue. The resulting preparation, free of its lysosomal counterparts, was used for the characterization of the enzyme and for further purification (lectin affinity chromatography, hydrophobic interaction chromatography, substrate-ligand affinity chromatography, ion-exchange chromatography, chromatography on activated thiol-Sepharose 4B). Only ion-exchange chromatography on DEAE-Sephacel appeared to improve the purity. The Michaelis constant was 0.46 mM for the substrate 4-methyl-umbelliferyl-2-acetamido-2-deoxy-beta-D-glucopyranoside. The enzyme was not inhibited by acetate or N-acetylgalactosamine. Inhibition by N-acetylglucosamine was competitive, with a Ki value of 8.0 mM. Inhibition by divalent metal ions increased in the order Fe less than Zn less than Cu. Dithiothreitol and beta-mercaptoethanol, at an optimum concentration of about 10 mM, stimulated the activity. The enzyme is apparently not a glycoprotein since it did not bind to various lectins, nor did sialidase change its isoelectric point.
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PMID:Isolation and further characterization of bovine brain hexosaminidase C. 726 95

Binding and phagocytosis of rat erythrocytes by liver and peritoneal macrophages were studied with a radioactive in vitro assay which yields quantitative data. Partial removal of sialic acids from the erythrocytes by Vibrio cholerae sialidase resulted in a marked increase of binding of the red cells by both liver and unstimulated peritoneal macrophages. Peritoneal macrophages stimulated by thioglycolate or starch, however, did not differentiate between control and desialylated erythrocytes. By inhibition experiments it was confirmed that rat peritoneal macrophages bind homologous sialidase-treated erythrocytes via a beta-D-galactose-specific lectin on the macrophage surface. While this attachment already occurs in buffer, serum was required for the subsequent phagocytosis. The possible involvement of factors of the complement system in the phagocytosis step was evidenced by a marked decrease of phagocytosis after heat inactivation of the serum. Based on these experiments, we propose a model of a two-step mechanism for the uptake of sialidase-treated erythrocytes by macrophages, comprising both the lectin and a receptor for serum components.
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PMID:Phagocytosis of sialidase-treated rat erythrocytes: evidence for a two-step mechanism. 730 7


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