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)

Keratan sulphate chains were isolated from bovine tracheal ring cartilage (15-18-month-old animals) after papain digestion of the tissue followed by ethanol fractionation, chondroitinase ABC digestion and alkaline borohydride reduction. The keratan sulphate chains were further purified by anion-exchange chromatography on a Pharmacia Mono-Q column in order to remove any contaminating chondroitin sulphate and O-linked oligosaccharides. The chains were then treated with keratanase and the digest was subjected to alkaline borohydride reduction, producing oligosaccharides with galactitol at their reducing ends. The reduced digest was chromatographed on a Nucleosil 5 SB anion-exchange column and individual oligosaccharides were isolated. One of these, oligosaccharide (I), was shown by 500 MHz 1H-n.m.r. spectroscopy to have the following structure: NeuAc alpha 2-3Gal beta 1-4GlcNAc(6SO4) beta 1-3Gal-ol (I) The structure of this oligosaccharide shows that keratan sulphate chains from bovine tracheal ring cartilage may be terminated with N-acetylneuraminic acid linked alpha (2-3) to an unsulphated galactose. Keratan sulphate chains were also isolated from bovine femoral head cartilage (15-18-month-old animals) using an identical protocol, but with keratanase which was subsequently shown to have sialidase activity. This yielded oligosaccharide (II), the unsialyated version of (I): Gal beta 1-4GlcNAc(6SO4) beta 1-3Gal-ol (II).
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PMID:A non-reducing terminal fragment from tracheal cartilage keratan sulphate chains contains alpha (2-3)-linked N-acetylneuraminic acid. 191 Mar 36

Human anti-S and anti-s eluates bound to glycophorin B on immunoblots from membranes of S+ and s+ red cells, respectively. Eluates of human anti-S were more efficiently prepared from sensitized trypsin-treated cells than from sensitized untreated cells. The results of immunoblotting membranes from enzyme-treated cells confirmed the serological findings: S and s antigens were not affected by treatment with trypsin or sialidase but were destroyed or much depressed by treatment with papain, pronase or alpha-chymotrypsin. Immunoblotting with anti-S or anti-s of membranes from cells with unusual MNS phenotypes confirms the involvement of glycophorin B in hybrid glycophorins; the existence of such hybrid glycophorins was deduced previously from serological work or immunoblotting with monoclonal antibodies. The presence of s-active glycophorin B in glycophorin (B-A)Dantu, in glycophorin BMiIII and in glycophorin (A-B)MiV was confirmed. The bands observed when Mit+ membranes were immunoblotted with anti-S supports the suggestion from serological work that the Mit antigen is associated with an altered S antigen.
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PMID:Immunoblotting of human red cell membranes: detection of glycophorin B with anti-S and anti-s antibodies. 239 72

Isoenzymes of alkaline phosphatase (EC 3.1.3.1) were separated by micro-scale two-dimensional electrophoresis, with isoelectric focusing in capillary gels in the first dimension and polyacrylamide gradient-gel electrophoresis in the second. The isoenzymes detected were identified by several treatments--e.g., incubation with sialidase, papain, Triton X-100, and wheat-germ agglutinin--and by comparison with alkaline phosphatase from liver microsomes. Liver and bone isoforms in normal sera showed overlapping isoelectric points but differed in molecular mass, estimated as 172 and 185 kDa, respectively. Sera of patients with liver disease showed several additional groups of alkaline phosphatase isoforms, two of which were found to consist of multi-molecular complexes. Others probably correspond to incompletely glycated enzyme proteins. A further isoform with a mass of about 250 kDa does not seem to correspond to any known isoform of alkaline phosphatase in serum. With this technique, we demonstrated intra- and interindividual variations of the placental alkaline phosphatase isoenzyme in pregnancy sera.
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PMID:Micro-scale two-dimensional electrophoresis of alkaline phosphatase from serum. 335 9

Crude extracts from Salvia sclarea seeds were known to contain a lectin which specifically agglutinates Tn erythrocytes (Bird, G. W. G., and Wingham, G. (1974) Vox Sang. 26, 163-166). We have purified the lectin to homogeneity by ion-exchange chromatography and affinity chromatography. The agglutinin was found to be a glycoprotein of Mr = 50,000, composed of two identical subunits of Mr = 35,000 linked together by disulfide bonds. The purified lectin agglutinates specifically Tn erythrocytes and, at higher concentrations, also Cad erythrocytes. Native A, B, or O red blood cells are not agglutinated by the lectin and, even after treatment with sialidase or papain, these cells are not recognized. Tn red cells present 1.45 X 10(6) accessible sites to the lectin which binds to these erythrocytes with an association constant of 1.8 X 10(6) M-1. On Cad red cells, 1.73 X 10(6) sites are accessible to the lectin which binds with an association constant of 1.0 X 10(6) M-1. The carbohydrate specificity of the S. sclarea lectin has been determined in detail, using well defined monosaccharide, oligosaccharide, and glycopeptide structures. The lectin was found to be specific for terminal N-acetylgalactosamine (GalNAc) residues. It binds preferentially alpha GalNAc determinants either linked to Ser or Thr (as in Tn structures) or linked in 1-3 to a beta GalNAc or to an unsubstituted beta Gal. Although more weakly, the lectin binds beta GalNAc residues linked in 1-4 to a beta Gal (as in Cad structures). It does not recognize beta GalNAc determinants linked in 1-3 to a Gal (as in globoside) or the alpha GalNAc residues of blood group A structures.
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PMID:Isolation and characterization of an N-acetylgalactosamine specific lectin from Salvia sclarea seeds. 377 23

1. Plasma membranes from rat liver or kidney inhibited the growth of hepatoma (AH-130) cells in vitro. AH-130 plasma membranes or erythrocyte ghosts inhibited the growth of AH-130 cells less effectively. The inhibitory activity of liver plasma membranes was lost by heat treatment, or mild protease (papain or bromelin, but not trypsin or pronase) treatment, whereas it was retained after sialidase treatment of delipidation by ethanol/ether. 2. Proteoglycan (proteoheparan sulfate) prepared from liver plasma membranes inhibited the growth of AH-130 cells, but heparan sulfate was less active. The inhibitory activity of liver plasma membranes seemed, however, not to be ascribable solely to proteoheparan sulfate associated with plasma membranes. 3. Preliminary investigation suggested that the molecular weight 40 000 component may be a major inhibitory principle in liver plasma membranes.
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PMID:Liver plasma membranes and proteoglycan prepared therefrom inhibit the growth of hepatoma cells in vitro. 702 39

The interaction of alkaline phosphatase (EC 3.1.3.1) with bismuth was studied. Among the tested alkaline phosphatases, bismuth was found to be the most effective inhibitor of the placental enzyme. Partial denaturation of the placental enzyme by papain digestion had little effect, if any, on the inhibition. Bismuth inhibition of the placental enzyme activity was more progressive with mixed glycosidase treatment than with sialidase treatment. The pH activity profile of the mixed glycosidase-treated placental enzyme was clearly shifted in the presence of bismuth. The mixed glycosidase-treated placental enzyme/bismuth mixture was more heat labile than the non-treated placental enzyme. Based on the results of kinetic studies, the inhibition mechanism of the placental enzyme by bismuth was shown to be of the competitive type, and the Ki value and Hill coefficient of the mixed glycosidase-treated placental enzyme was found to be 92 mu mol/l and 2.25, respectively. L-Phenylalanine does not interfere with the inhibitory effect of bismuth on alkaline phosphatase. Inorganic phosphate, on the other hand, appears to disturb bismuth bindings.
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PMID:Inhibition of alkaline phosphatase by bismuth. 729 84

The apparent association velocity constant (k'c) was determined before and after disruption of the red blood cell membrane in one of several ways: 1) radiation of the cells using a 137Cs source did not significantly alter k'c (95 +/- 39.3 and 118 +/- 35.5 mM-1.s-1), 2) incubation of the cells with sialidase produced no change in k'c (112 +/- 42.6 and 123 +/- 46.8 mM-1.s-1), 3) using papain for the incubation similarly produced no significant alteration in k'c (94 +/- 21.2 and 113 +/- 51.8 mM-1.s-1), 4) a radiomimetic agent p-chloromercuribenzene sulfonate likewise produced no significant alteration in k'c (128 +/- 16.3 and 122 +/- 3.5 mM-1.s-1), and 5) employing phospholipase C to disrupt the membrane k'c did not significantly change (115 +/- 15.3 and 112 +/- 8.7 mM-1.s-1). We conclude that either O2 traverses the membrane in a manner uninfluenced by the manipulations here employed, or that the membrane offers no significant resistance to the speed of O2 uptake.
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PMID:Resistance of red blood cell membrane to oxygen uptake. 740 13

We investigated whether sera from chronic Chagasic patients and animals infected with Trypanosoma cruzi inhibit the removal of sialic acid from human erythrocytes and the transfer of sialic acid from sialyllactose to [14C]lactose in the reactions catalyzed by the parasite trans-sialidase. Sera from Swiss mice and Calomys callosus animals infected with three different T. cruzi strains inhibit both reactions. Inhibition increases during the infection, reaching maximal levels when the parasitemia decreases. Among 44 sera of untreated chronic Chagasic patients, 40 inhibit both reactions. Inhibition is observed with total, defatted sera or with purified immunoglobulins. Whereas most of the inhibitory antibodies from Chagasic patients react with the papain fragment of trans-sialidase in immunoblots, a few patients have noninhibitory antibodies that react only with the entire trans-sialidase. These findings may be relevant for the pathology of Chagas' disease.
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PMID:Sera from chronic Chagasic patients and rodents infected with Trypanosoma cruzi inhibit trans-sialidase by recognizing its amino-terminal and catalytic domain. 800 83

trans-Sialidase isolated from trypomastigote forms of Trypanosoma cruzi, the protozoan parasite that causes Chagas' disease, is multimeric and heterogeneous in size. We show here that limited proteolysis of tans-sialidase with papain yields a single monomeric polypeptide chain of 70 kDa that conserves full enzymatic activity on soluble and membrane-bound substrates. The papain fragment lacks most of the 12-amino acid repeats of the carboxyl-terminal domain that comprises about 50% of the native trans-sialidase. When injected into rabbits, the papain-generated fragment induces antibodies that inhibit trans-sialidase activity and trypomastigote sialylation. The repeats are also not required for the stability of the enzyme or for the correct folding during the biosynthesis in Escherichia coli, but seem essential for trans-sialidase oligomerization. We conclude that trans-sialidase is composed of two structurally and functionally independent domains.
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PMID:A proteolytic fragment of Trypanosoma cruzi trans-sialidase lacking the carboxyl-terminal domain is active, monomeric, and generates antibodies that inhibit enzymatic activity. 813 17

Fifteen examples of red cells are described which showed discrepant reactivity on routine grouping with two monoclonal anti-D typing reagents, HAM-A being negative and MAD-2 strongly positive. The reaction profile of these cells with a number of monoclonal anti-D characterised the samples into two new variant groups, DHMi and DHMii. DHMi was characterised by a negative reaction with BRAD-8 and DHMii by a negative reaction with BRAD-5. DHMi cells were found to have a papain-sensitive site, identified by Mab 21 G6, which was not detectable in DHMii. The presence of allo-anti-D in one case of DHMi suggests a partial D in these individuals. The positive reaction of HAM-A with sialidase- and endo-F-treated DHMii cells suggests that sialic acid and/or N-glycans could possibly be involved in blocking the reaction with untreated cells. All samples typed as C-E+. One was e negative while the rest had variable depression of the e and f antigens. Marginal depression of E was seen with those DHMi cells tested, but not with DHMii cells. Data from family studies suggest that the variant D in both DHMi and DHMii is inherited as a cDE gene complex and is controlled by the RH locus.
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PMID:Identification of two new D variants, DHMi and DHMii using monoclonal anti-D. 857 37


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