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

---

Query: EC:3.1.1.53 (sialidase)
2,694 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Glycoproteins in the normal airway surface epithelium and submucosal glands of 13 Large White pigs were studied from birth to adult life using alcian blue (AB) staining at pH 2.6 or at pH 1.0, with and without sialidase digestion, and by the combination of AB and PAS (AB/PAS) stains. Immediately after birth the percentage of cells producing acidic and neutral glycoproteins increased in both airway surface epithelium and submucosal glands. In the airway surface epithelium, the percentage of mucus-secreting cells producing sulphated glycoprotein increased with age, whereas in the submucosal glands the glycoproteins were mainly sulfated between birth and 3 days and sialylated between 3 days and adult life. The percentage of cells producing neutral glycoprotein in the airway surface epithelium increased during the first 24 h of life after which there was little change with age. In the submucosal glands, however, the greatest increase in the percentage of cells producing neutral glycoprotein occurred between 7 days and adult life. The rapid increase of intracellular glycoprotein production at birth and the presence of the same types of glycoprotein in the immature pig and mature human lung, suggest that the pig may be a useful model in which to study mechanisms and changes of glycoprotein synthesis and secretion during lung development.
...
PMID:Development of the airway epithelium and submucosal glands in the pig lung: changes in epithelial glycoprotein profiles. 380 Dec 96

We previously reported that the oligosaccharide chains of hog gastric mucin were degraded by unidentified subpopulations numbering approximately 1% of normal human fecal bacteria. Here we report on the enzyme-producing properties of five strains of mucin oligosaccharide chain-degrading bacteria isolated from feces of four healthy subjects. Four were isolated from the greatest fecal dilutions yielding mucin side chain-degrading activity in culture, and thus were the numerically dominant side chain-degrading bacteria in their respective hosts. Three were Ruminococcus strains and two were Bifidobacterium strains. Two Ruminococcus torques strains, IX-70 and VIII-239, produced blood group A- and H-degrading alpha-glycosidase activities, sialidase, and the requisite beta-glycosidases; these strains released greater than 90% of the anthrone-reacting hexoses from hog gastric mucin during growth in culture. The Bifidobacterium strains lacked A-degrading activity but were otherwise similar; these released 60-80% of the anthrone-reacting hexoses but not the A antigenic structures from hog gastric mucin. Only Ruminococcus AB strain VI-268 produced blood group B-degrading alpha-galactosidase activity, but this strain lacked beta-N-acetylhexosaminidases to complete degradation of B antigenic chains. When this strain was co-cultured with a strain that produced beta-N-acetylhexosaminidases, release of hexoses from blood group B salivary glycoprotein increased from 50 to greater than 90%, and bacterial growth was enhanced. The glycosidases required for side chain degradation were produced by these strains in the absence of mucin substrate, and a substantial fraction of each activity in stationary phase cultures was extracellular. In contrast, none of 16 other fecal Bacteroides, Escherichia coli, Streptococcus faecalis, and Bifidobacterium strains produced ABH blood group-degrading enzymes; other glycosidases produced by these strains were predominantly cell bound except for extracellular beta-N-acetylhexosaminidases produced by the five S. faecalis strains. We conclude that certain Bifidobacterium and Ruminococcus strains are numerically dominant populations degrading mucin oligosaccharides in the human colon due to their constitutive production of the requisite extracellular glycosidases including blood group antigen-specific alpha-glycosidases. These properties characterize them as a functionally distinct subpopulation of normal human enteric microflora comprised of specialized subsets that produce blood group H antigen-degrading glycosidases alone or together with either blood group A- or B-degrading glycosidases.
...
PMID:Mucin degradation in human colon ecosystems. Isolation and properties of fecal strains that degrade ABH blood group antigens and oligosaccharides from mucin glycoproteins. 392 Feb 48

The specificities of one viral and five bacterial sialidases were investigated by 1H-NMR-spectroscopy with substrates or substrate mixtures containing two sialic acid residues of different linkage types. This technique allows - in contrast to the methods used before - the simultaneous determination of the rates of hydrolysis of both NeuAc linkages in a single experiment. The substrate specificities of the enzymes are discussed on the basis of the relation of the rate constants k/k'. The data obtained are more exact and more informative than those of separate experiments as reported previously. Among the enzymes investigated, i.e. sialidases of fowl plague virus (FPV = VKH), Clostridium perfringens (CP), Vibrio cholerae (VC), Bifidobacterium bifidum var. pennsylvanicum (BBif), Bifidobacterium lactentis (BLac), and Arthrobacter ureafaciens (AU), the activity of the viral sialidase VKH shows the highest, the activities of the Bifidobacterium sialidases the lowest dependence on the nature and on the linkage type of the different substrates. All sialidases preferentially cleave the NeuAc alpha 2-3-Gal linkage with the exception of the enzyme of Arthrobacter ureafaciens (AU) which shows a higher affinity to alpha 2-6 linkages. However, this does not apply to the side-arm-linked NeuAc alpha 2-6 structure in NeuAc alpha 2-3 Gal beta 1-3 (NeuAc alpha 2-6)-GlcNAc beta 1-3Gal beta 1-4Glc (Substrate B). This substrate in generally cleaved very slowly and is hardly affected by the viral enzyme. After the alpha 2-3 linkage, the alpha 2-8 bond in NeuAc alpha 2-8 NeuAc alpha 2-3 Gal beta 1-4Glc(Substrate A) is most susceptible for the sialidases VKH, CP and VC. An elongation of the carbohydrate chain (Substrate D) is accompanied by a reduction of the rate of cleavage for all enzymes. The experiments with alpha 1-acid glycoprotein, fetuin, and with the glycopeptides obtained by proteolytic degradation of the latter, revealed the same specificity towards the alpha 2-3 and the alpha 2-6 linkages as the oligosaccharides. Influenced by the chemical nature and the size of the substrate, NeuAc is released from the native alpha 1-acid glycoprotein more quickly than from the corresponding glycopeptide. All sialidases investigated so far are strictly exo-enzymes as could be demonstrated by the cleavage of NeuAc alpha 2-8 NeuAc alpha 2-3 Gal beta 1-4Glc (Substrate A).
...
PMID:[H-NMR spectroscopy. Specificity of microbial sialidases against complex substrates]. 609 53

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.
...
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

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.
...
PMID:Glycoprotein C of herpes simplex virus type 1: characterization of O-linked oligosaccharides. 631 56

A sialidase (neuraminidase, acylneuraminosyl hydrolase, EC 3.2.1.18) has been discovered and isolated from Gardnerella vaginalis (ex. Haemophilus vaginalis), a possibly pathogenic inhabitant of the female genital tract. Bacteria were grown in peptone-yeast-extract medium with 2.0 mM N-acetylmannosamine as enzyme inductor under CO2 atmosphere. Sialidase activity was found in the bacterial sediment and in the culture medium. The enzyme was liberated from the cells by ultrasonic treatment. Purification was performed by 60-80% ammonium sulfate precipitation and by column chromatography on Sepharose CL-6B and Sephadex G 200. The enzyme revealed a molecular weight in the range of Mr 75 000 and a pH optimum at 5.5. Among the different types of NeuAc-containing glycoconjugates, the enzyme exhibits its highest activities towards the globular glycoproteins alpha 1-acid glycoprotein and fetuin. Taking their cleavage rate as 100, it is around 55 for II3NeuAc-Lac, 45 for bovine submaxillary mucin, 35 for II6NeuAc-Lac and IV3, III6NeuAc2-LcOse4. The rates for III8,II3NeuAc2-Lac, gangliosides and colominic acid are below 20. Due to its specificity pattern, the enzyme may play a role in the pathogenic process of G. vaginalis infections.
...
PMID:A newly discovered sialidase from Gardnerella vaginalis. 633 32

The glycoprotein from Friend murine leukemia virus was digested with protease from Staphylococcus aureus V8. A glycopeptide comprising the N-terminal glycosylation site (Asn-12) was isolated from the mixture of fragments and analyzed by amino acid sequencing and methylation-capillary gas chromatography-mass spectrometry before and after treatment with sialidase from Vibrio cholerae. Asn-12 was thus found to be substituted by a family of partially sialylated, fucosylated, and intersected glycoprotein N-glycans of the hybrid type.
...
PMID:The glycoprotein 71 of ecotropic Friend murine leukemia virus. Structure of the oligosaccharides linked to asparagine-12. 637 Jul 24

Lines of KB cells resistant to Sendai virus-induced cytolysis have been isolated and characterized (Toyama, S., Toyama, Su., and Uetake, H. (1977) Virology 76, 503-515). This study is concerned with the nature of this mutation. Plasma membrane fractions from Sil cells were found to have decreased amount of sialic acid and the same amount of galactose as compared to the membranes from parental KB cells. Sil cells exhibited an increase in sensitivity to toxic effects of ricin and a decrease in sensitivity to wheat germ agglutinin. Binding of wheat germ agglutinin to Sil cells was markedly decreased. Several membrane glycoproteins of Sil cells migrated slightly faster than the corresponding bands of wild type membrane when examined by gel electrophoresis in sodium dodecyl sulfate. Sil cells had decreased sialyltransferase activity that catalyzed the transfer of sialic acid residues from CMP-N-acetylneuraminic acid to glycoprotein acceptors containing Gal beta 1 leads to 3GalNAc alpha 1 leads to O-Ser(Thr) chain. The decreased enzyme activity could not be accounted for by the presence of inhibitors, altered pH optimum, or increased sialidase or CMP-sialic acid hydrolase activities. These results indicate that a molecular basis for the Sil cell phenotype might be the deficiency of sialyltransferase.
...
PMID:Deficient cytidine monophospho-N-acetylneuraminic acid: glycoprotein sialyltransferase activity in a clone of KB cells with altered cell fusion ability. 640 1

A deficiency of glycoprotein neuraminidase (sialidase, acylneuraminyl hydrolase, EC 3.2.1.18) activity was found in fibroblasts from a patient with the clinical symptoms of Morquio disease type A (mucopolysaccharidosis IV A). Residual neuraminidase activity was about 5% of the mean normal activity. N-Acetylgalactosamine-6-sulfate (GalNAc-6-S) sulfatase activity was reduced to less than 1% of normal with a pH-optimum of 3.0 as expected for the severe form of Morquio disease. In peripheral leucocytes of the patient, however, neuraminidase activity but not Ga1NAc-6-S sulfatase activity was in the normal range. Mixing experiments excluded the presence of excessive amounts of inhibitors of neuraminidase activity.
...
PMID:Partial deficiency of glycoprotein neuraminidase in some patients with Morquio disease type A. 642 47

Sialidase activities have been studied in bovine thyroid using sialoglycolipids, sialoglycoproteins, sialo-oligosaccharides and fluorogenic 4-methylumbelliferyl-alpha-D-N-acetylneuraminate as substrates. No sialidase activity could be detected towards native glycoprotein substrates. From enzyme kinetics, effector data and more convincingly from subcellular studies it became clear that in bovine thyroid at least two sialidase activities were present, a sialyllactitol sialidase confined to the lysosomal membrane and a glycolipid sialidase residing in the plasma membrane and displaying the features of a true ectoenzyme. The lipid requirement for full enzyme activity supported the membrane bound character of both sialidase activities. A soluble sialidase activity could not be demonstrated. After solubilization by CHAPS treatment, partial purification of the sialyllactitol sialidase could be achieved by affinity chromatography (Sepharose diamino dipropylamino-N-acetylneuraminic acid). The purified enzyme was extremely labile. Titration of the sialidase preparation with amino acid modifying agents revealed that sulfhydryl- and tryptophanyl groups were essential for the sialidase action.
...
PMID:Characterization, purification, and subcellular localization of bovine thyroid sialidases. 652 Jan 26


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---