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)

A broad variety of normal human tissues were examined for the expression of Thomsen-Friedenreich (TF)-related histo-blood group antigens, TF (Gal beta 1-3GalNAc alpha 1-R), Tn (TF precursor, GalNAc alpha 1-R), sialosyl-Tn (NeuAc alpha 2-6GalNAc alpha 1-R), considered to be useful in cancer diagnosis and immunotherapy, and sialosyl-TF, the cryptic form of TF. These antigens or, more correctly, glycotopes, were determined by immunohistochemistry with at least two monoclonal antibodies (mAbs) each (except sialosyl-TF) as well as by lectin histochemistry. For a better dissection of sialosyl-TF and TF glycotopes, tissue sections were pretreated with galactose oxidase or the galactose oxidase-Schiff sequence. Staining with mAbs appeared to be more restricted than with the lectins used. Distribution patterns among normal epithelia were different for all four antigens. These antigens were also detected in some non-epithelial tissues. They can be classified in the following sequence according to the frequency of their occurrence in normal tissues: sialosyl-TF > > sialosyl-Tn > Tn > TF. Most of the positively staining sites for TF, Tn, and sialosyl-Tn are located in immunologically privileged areas. The complex results obtained with anti-TF mAbs (after treatment of the tissue sections with sialidase from Vibrio cholerae) and the lectins amaranthin and jacalin revealed a differential distribution of the subtypes of sialosyl-TF [NeuAc alpha 2-3Gal beta 1-3GalNAc alpha 1-R and Gal beta 1-3 (NeuAc alpha 2-6)GalNAc alpha 1-R] in normal human tissues. From our data it can be inferred that TF, Tn, and sialosyl-Tn are promising targets for a cancer vaccine.
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PMID:Thomsen-Friedenreich-related carbohydrate antigens in normal adult human tissues: a systematic and comparative study. 887 80

Incubation of human vitamin D3-binding protein (Gc protein), with a mixture of immobilized beta-galactosidase and sialidase, efficiently generated a potent macrophage activating factor, a protein with N-acetylgalactosamine as the remaining sugar. Stepwise incubation of Gc protein with immobilized beta-galactosidase and sialidase, and isolation of the intermediates with immobilized lectins, revealed that either sequence of hydrolysis of Gc glycoprotein by these glycosidases yields the macrophage-activating factor, implying that Gc protein carries a trisaccharide composed of N-acetylgalactosamine and dibranched galactose and sialic acid termini. A 3 hr incubation of mouse peritoneal macrophages with picomolar amounts of the enzymatically generated macrophage-activating factor (GcMAF) resulted in a greatly enhanced phagocytic activity. Administration of a minute amount (10-50 pg/mouse) of GcMAF resulted in a seven- to nine-fold enhanced phagocytic activity of macrophages. Injection of sheep red blood cells (SRBC) along with GcMAF into mice produced a large number of anti-SRBC antibody secreting splenic cells in 2-4 days.
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PMID:Structural definition of a potent macrophage activating factor derived from vitamin D3-binding protein with adjuvant activity for antibody production. 907 Jun 63

A serum glycoprotein, Gc protein (vitamin D3-binding protein), can be converted by beta-galactosidase of B cells and sialidase of T cells to a potent macrophage-activating factor (MAF), a protein with N-acetylgalactosamine as the remaining sugar moiety. Thus, Gc protein is the precursor for MAF. Treatment of Gc protein with immobilized beta-galactosidase and sialidase generates a remarkably high titered macrophage-activating factor (GcMAF). When peripheral blood monocytes/ macrophages (designated macrophages) of 33 systemic lupus erythematosus patients were incubated with GcMAF (100 pg/ml), the macrophages of all patients were activated as determined by superoxide generation. However, the precursor activity of patient plasma Gc protein was lost or reduced in these patients. Loss of the precursor activity was the result of deglycosylation of plasma Gc protein by alpha-N-acetylgalactosaminidase activity found in the patient plasma. Levels of plasma alpha-N-acetylgalactosaminidase activity in individual patients had an inverse correlation with the MAF precursor activity of their plasma Gc protein. Deglycosylated Gc protein cannot be converted to macro-phage-activating factor. The resulting defect in macro-phage activation may lead to an inability to clear pathogenic immune complexes. Thus, elevated plasma alpha-N-acetylgalactosaminidase activity resulting in the loss of MAF precursor activity and reduced macro-phage activity may play a role in the pathogenesis of systemic lupus erythematosus.
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PMID:Deglycosylation of serum vitamin D3-binding protein by alpha-N-acetylgalactosaminidase detected in the plasma of patients with systemic lupus erythematosus. 907 53

The sugar structures of the glycoconjugates in pleomorphic adenoma of the lacrimal gland were analyzed by examining the binding sites of 5 biotinylated lectins on tissue sections with or without sialidase digestion. Both galactose (Gal) beta 1,3 N-acetylgalactosamine and Gal beta 1,4 N-acetylglucosamine were present on the surfaces of ductal basal cells and stromal cells. The galactsyl residues in the glycoconjugates of ductal basal cells were either sialylated or exposed, whereas those of stromal cells were all sialylated. Since the synthesis of sugar chains of glycoconjugates is terminated by sialylation, their structure may mature as they progress from ductal basal cells to stromal cells.
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PMID:[Lectin-histochemical analysis of pleomorphic adenoma of the lacrimal gland]. 913 76

The sugar residues in glycoconjugates present in the parotid and mandibular glands of the adult fallow-deer were detected and characterized by using a battery of eight different lectin-horseradish peroxidase conjugates. In some cases a treatment with sialidase preceded the lectin staining. Parotid secretory cells produced glycoconjugates with N-acetylgalactosamine, N-acetylglucosamine and mannose residues. Mucous acinar cells were the most reactive sites of the mandibular gland and contained conspicuous quantities of oligosaccharides with terminal sialic acid radicals. Galactosil-(beta 1-->3)N-acetylgalactosamine was the most abundant penultimate sugar linked to N-acetylneuraminic acid. Mandibular mucous cells also presented N-acetylglucosamine and sialylated components with the terminal dimer sialic acid-N-acetylgalactosamine. Demilunar cells contained glycoconjugates with fucose and mannose residues. The apical surface of duct cells was stained by all the lectins.
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PMID:Histochemical study of lectin binding in the major salivary glands of adult fallow-deer (Dama dama L.). 915 Aug

To clarify the relation between the mechanism of apoptosis in tumor tissues and sialic acids on the termini of sugar chains of glycoconjugates, a case of squamous cell carcinoma was examined using immunohistochemistry and glycohistochemistry. Immunohistochemistry and in situ hybridization histochemistry suggested that sialylation by the sialyltransferase in dominant in tumor cells, whereas hydrolysis of sialic acids by the sialidase is dominant in apoptotic bodies. Lectin histochemistry revealed that sialic acid alpha 2, 3 galactose beta 1, 3 N-acetylgalactosamine (Gal beta 1, 3 GalNAc) is present on the surfaces of tumor cells, and Gal beta 1, 3 GalNAc is present on those of apoptotic bodies. The exposed Gal beta 1, 3 GalNAc owing to the decrease in sialic acids on the surfaces of apoptotic bodies may be recognized by the C-type lectin on the macrophage for phagocytosis.
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PMID:[Glycohistochemical analysis of apoptotic bodies in eyelid tumor]. 925 24

Because the polypeptide core of alpha-dystroglycan is encoded by a single gene, the difference in apparent molecular mass between alpha-dystroglycans expressed in various tissues is presumably due to differential glycosylation. However, little is presently known about the tissue-specific differences in alpha-dystroglycan glycosylation and whether these modifications may confer functional variability to alpha-dystroglycan. We recently observed that laminin-1 binding to skeletal muscle alpha-dystroglycan was dramatically inhibited by heparin, whereas the binding of commercial merosin to skeletal muscle alpha-dystroglycan was only marginally inhibited (Pall, E. A., Bolton, K. M., and Ervasti, J. M. (1996) J. Biol. Chem. 3817-3821). In contrast to 156-kDa skeletal muscle alpha-dystroglycan, both laminin-1 and merosin binding to 120-kDa brain alpha-dystroglycan were sensitive to heparin. We have now examined the laminin binding properties of 140-kDa alpha-dystroglycan purified from cardiac muscle and observed that like skeletal muscle alpha-dystroglycan, heparin inhibited cardiac alpha-dystroglycan binding to laminin-1, but not to merosin. On the other hand, cardiac and brain alpha-dystroglycans could be distinguished from skeletal muscle alpha-dystroglycan by their reactivity with the terminal GalNAc-specific lectin Vicia villosa agglutinin. Interestingly, skeletal muscle alpha-dystroglycan became reactive with V. villosa agglutinin upon digestion with sialidase from Clostridium perfringens, Arthrobacter neurofaciens, or Streptococcus, but not Vibrio cholerae or Newcastle disease virus sialidase. While none of the sialidase treatments affected the laminin binding properties of alpha-dystroglycan, the sum of our results suggests that skeletal muscle alpha-dystroglycan contains a novel sialic acid residue linked alpha2-6 to GalNAc. These properties are also consistent with the cellular characteristics of a GalNAc-terminated glycoconjugate recently implicated in neuromuscular synaptogenesis. Thus, variations in alpha-dystroglycan sialoglycosylation may prove as useful markers to further elucidate the role of alpha-dystroglycan glycoforms in different tissues and perhaps within a single cell type.
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PMID:Tissue-specific heterogeneity in alpha-dystroglycan sialoglycosylation. Skeletal muscle alpha-dystroglycan is a latent receptor for Vicia villosa agglutinin b4 masked by sialic acid modification. 926 82

The interaction between a surface protein antigen (PAc) of Streptococcus mutans and human salivary agglutinin was analyzed with a surface plasmon resonance biosensor. The major component sugars of the salivary agglutinin were galactose, fucose, mannose, N-acetylglucosamine, N-acetylgalactosamine, and N-acetylneuraminic acid. Binding of salivary agglutinin to PAc was calcium dependent and heat labile and required a pH greater than 5. Binding was significantly inhibited by N-acetylneuraminic acid and alpha2,6-linked sialic acid-specific lectin derived from Sambucus sieboldiana in a dose-dependent manner. Pretreatment of the salivary agglutinin with sialidase reduced the binding activity of the agglutinin to the PAc molecule. The agglutinin was dissociated into high-molecular-mass glycoprotein and secretory immunoglobulin A (sIgA) components by electrophoretic fractionation in the presence of 1% sodium dodecyl sulfate and 1% 2-mercaptoethanol. Neither of the components separated by electrophoretic fractionation, high-molecular-mass glycoprotein or sIgA, bound to the PAc molecule. Furthermore, the high-molecular-mass glycoprotein strongly inhibited the binding of the native salivary complex to PAc. These results suggest that the complex formed by the high-molecular-mass salivary glycoprotein and sIgA is essential for the binding reaction and that the sialic acid residues of the complex play an important role in the interaction between the agglutinin and PAc of S. mutans.
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PMID:Binding of salivary glycoprotein-secretory immunoglobulin A complex to the surface protein antigen of Streptococcus mutans. 942 47

A battery of horseradish peroxidase-conjugated lectins (Con A, WGA and DBA), as well as conventional histochemical techniques (PAS, saponification, Alcian Blue pH 0.1, 1, 2.5, chlorhydric hydrolisis, sialidase, Bromophenol blue, Tioglycollate reduction and Ferric-ferricyanide-FeIII) were used to study the content and distribution of carbohydrates, proteins and glycoconjugate sugar residues on the skin and on the lymphocystis-infected cells of gilthead seabream, Sparus aurata. Variable amounts of glycoproteins containing sialic acid, N-acetyl-D-glucosamine, N-acetyl-D-galactosamine, mannose and/or glucose residues were observed in the cuticle and mucous cells of the corporal skin, tails and fins. Germinative and epithelial cells of the epidermis contained glycogen, proteins, carboxylated groups, as well as glycoproteins with mannose and/or glucose and N-acetyl-D-galactosamine residues. Hyaline capsule of the mature lymphocystis-infected cells was strongly stained with PAS, Alcian Blue (pH 0.5 and 2.5) and weakly positive with Alcian Blue (pH 1). Con A reacted with the granular cytoplasm, specially around hyaline capsule, and with the basophilic intracytoplasmic inclusions developed in mature lymphocystis-infected cells of Sparus aurata skin. These sugar residues (mannose and/or glucose), as well as N-acetyl-D-glucosamine and/or sialic acid and N-acetyl-D-galactosamine were not detected in the hyaline capsule of the lymphocystis disease.
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PMID:Histochemical study of lymphocystis disease in skin of gilthead seabream, Sparus aurata L. 947 32

An ultrastructural analysis of lectin receptors on the submandibular glands from mice of both sexes was performed utilizing horseradish peroxidase-labelled lectins in conjunction with antiperoxidase antibody and protein A-gold. Both qualitative and quantitative sex-related differences in terminal sugar expression within secretory granules were detected. Following sialidase digestion, also subterminal acceptor sugars for terminal sialic acids, proved to be differentially expressed in the submandibular glands of males and females. Heterogeneous distribution of sialoglycoconjugates characterized by the terminal disaccharide sialic acid-beta-galactose was found to occur in female acinar cells. Also DBA reactive sites indicating the presence of terminal alpha-N-acetylgalactosamine discriminated between male and female acinar secretory glycoconjugates. This difference was emphasized by sialidase pretreatment that evidenced a marked occurrence of sialic acid subtended to alpha-N-acetylgalactosamine in males in contrast to a modest presence in females. The different sialylation patterns of acinar cell secretory products, probably related to a different expression of O- and N-linked sialoglycoconjugates, give insight into the sexual dimorphism of the mouse submandibular gland known until recently for the convoluted granular tubules.
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PMID:Sialoglycoconjugate dimorphism of the mouse submandibular gland acinar cells. Ultrastructural evidence by lectin-protein A-gold probes and sialidase digestion. 947 44


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