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 exotoxin produced by Vibrio cholerae is rapidly and firmly bound to the outer membrane of mammalian cells. With simple in vitro and in vivo methods and very pure gangliosides and allied glycolipids we have demonstrated that the monosialosylganglioside GM1 is the natural receptor for the cholera toxin. This ganglioside binds the toxin with a high affinity and inactivates it. The inactive derivative, choleragenoid toxoid has the same affinity to GM1 as the toxin. Ganglioside GM1 was isolated from the small intestinal mucosa of man, pig and ox in amounts of 0.1, 2.0 and 43 nmoles per g mucosa, respectively. These very large differences in the ability of the mucosal cells to bind cholera toxin. Exogenous GM1 was incorporated in vitro and in vivo in intestinal mucosal cells. The incorporation of GM1 increased the number of toxin-binding sites and increased the secretion of fluid in the gut. Vibrio cholerae sialidase did not hydrolyse the di- and trisialogangliosides of intact mucosal cells to the parent GM1-ganglioside, neither did it increase the number of cholera toxin-binding sites.
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PMID:Interaction of cholera toxin and ganglioside G(M1). 93 47

1. Alkaline phosphatase (EC 3.1.3.1) from human liver was solubilized from the homogenate using 0.2% Triton X-100 containing 0.2 M lithium 3,5-diiodosalicylate, and the pellet obtained was resolubilized with 20% n-butanol. The procedure resulting in 3842-fold purification included acetone fractionation, ammonium sulfate precipitation, DEAE-cellulose chromatography, Sephadex G-200 gel filtration, hydroxyapatite gel chromatography and further concanavalin A/Sepharose 4B affinity chromatography. 2. The highly purified enzyme showed one major protein band on acrylamide gel electrophoresis at pH 8.6, and exhibited one-seventh of the alkaline p-nitrophenylphosphatase activity in the hepatic enzyme preparation contains of the alkaline pyrophosphatase activity. 3. The highly purified enzyme was a sialic-acid containing glycoprotein. 4. Sialidase-treated hepatic enzyme clearly presented the phenomenon of delayed mobility, and the delayed enzyme fraction stained more strongly than that of non-treated hepatic alkaline phosphatase. 5. In order to investigate the role of the carbohydrate region(s) of the hepatic alkaline phosphatase molecule on substrate binding, the effect of sialidase treatment on the rate of substrate inhibition of alkaline phosphatase was studied. In the case of hepatic enzyme without sialidase, substrate inhibition of alkaline phosphatase activity was clearly shown, while in the case of the hepatic enzyme with sialidase, there was hardly any substrate inhibition in the range of 1-8 mM p-nitrophenylphosphate.
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PMID:Partial purification and some properties of human liver alkaline phosphatase. 94 51

Studies were designed to correlate the sialic acid content of endometrial tissue and sialidase activity of endometrial tissue, uterine fluid, and plasma obtained from normally cyclic, pregnant, and lactating women, and from cases with disturbed endometrial differentation due to the use of copper IUDs and contraceptive steroids. The results revealed that an antagonistic effect exists between endometrial sialidase and sialic acid content. However, in all the cases of uterine dysfunctions, the sialidase activity in uterine fluid and plasma decreased, whereas it increased during pregnancy. These data seem to indicate an endocrine regulation of sialidase and sialic acid content of endometrial tissue.
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PMID:Sialic acid and sialidase activity in human endometrial tissue, uterine fluid and plasma under different conditions of uterine dysfunction. 94 46

The binding to normal and sialidase-treated human erythrocytes and lymphocytes of four 125I-labeled lectins [Maackia amurensis hemagglutinins (MAM and MAH), Ricinus communis hemagglutinin (RCH), and Bauhinia purpurea hemagglutinin (BPH)] was studied in detail. The quantitative inhibition assays against the lectin binding to the cells were also performed with various glyco-proteins and glycopeptides as inhibitors. The comparison of the inhibition constants of the inhibitors thus obtained with the association constants of the lectins to the cells permitted estimation of the relative receptor activities of cell surface glyco-proteins toward the lectins.
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PMID:Elucidation of lectin receptors by quantitative inhibition of lectin binding to human erythrocytes and lymphocytes. 97 78

A quantitative analysis has been made of the glycoproteins present in the goblet cells of the epidermis, gill filaments and gill lamellae of three species of teleost fish. The glycoproteins have been identified by a combination of techniques, including the use of the enzyme sialidase followed by Alcian Blue staining, at PH 2.6 or 1.0, in combination with periodic acid-Schiff. The selected fish were representative of species living in marine, freshwater and estuarine environments. The range of glycoproteins identified in these fish was similar to that found in mammalian tissue in that both neutral and acid glycoproteins were present, the latter included both sialomucins sensitive and resistant to sialidase, and sulphomucin. A single goblet cell contained either neutral or acid glycoproteins alone or in combination. Only the epidermis of the plaice and rainbow trout contained uniform cell populations producing acid glycoproteins, the former sulphomucin and the latter mainly sialomucin. At each site in the flounder and in the gill epithelia of the plaice and rainbow trout, the goblet cell population was mixed, with cells producing each type of glycoprotein. The number of goblet cells producing each type of glycoprotein varied at each tissue site.
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PMID:Identification of glycoproteins in goblet cells of epidermis and gill of plaice (Pleuronectes platessa L.), flounder (Platichthys flesus (L.)) and rainbow trout (Salmo gairdneri Richardson). 99 52

Sialic acid has been detected on the erythrocyte surface of a number of different species of animals. The objective of this investigation was to determine the physiological significance of these sialyl residues to the viability of erythrocytes in circulation. Methods have been described for the determination of total sialic acid on red blood cells and the conditions under which it may be released with sialidase. Chicken, dog, goat, and rabbit were chosen for these studies because of the differences in the amount (3 X 10(6) - 72 X 10(6) resides per erythrocyte), and type (N-acetyl-or N-glycolyl-neuraminic acids) of sialic acid found on the surface of their erythrocytes. Radioactive tagging with Na251CrO4 was used to monitor the effect of sialidase on the viability of erythrocytes upon autologous transfusion. By the two criteria used to assess the viability of erythrocytes-the percentage of erythrocytes surviving 24 hr after the autologous transfusion, and the half-life of those red blood cells in circulation that survive the first 24 h after the autologous transfusion, and the half-life of those red blood cells in circulation that survive the first 24 hr-it is apparent that the presence of sialic acid on the cell surface is crucial for the survival of nonnucleated mammalian erythrocytes. The loss of viability of dog erythrocytes can be elicited by the removal of approximately 10% of the total sialic acid. In marked contrast to the behavior of mammalian erythrocytes, sialidase-treated chicken erythrocytes appear to retain their viability in circulation.
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PMID:Effect of sialidase on the viability of erythrocytes in circulation. 100 55

Ganglioside GM1 was isolated from the small intestinal mucosa of man, pig, and beef and amounted to 0.1, 2.0, and 43 nmol per g fresh weight, respectively. These differences in GM1 content were associated with a quantitatively differing ability of the mucosal cells to bind cholera toxin. Human cells bound about 15,000 toxin molecules when saturated with the toxin, porcine cells 120,000, and bovine cells 2,600,000 molecules. The association constant (KA) of the cholera toxin binding was, for cells of all three species, about 10(9) liters/mol. Exogenously added GM1 ganglioside was incorporated in intestinal mucosal cells as well as in intact rabbit small bowel. The increment in GM1 was associated with a correspondingly increased number of binding sites for cholera toxin, whereas KA was unchanged. GM1 incorporation increased the sensitivity of the rabbit small bowel to the diarrheogenic action of cholera toxin. Vibrio cholerae sialidase hydrolyzed isolated intestinal diand trisialogangliosides to GM1. However, the enzyme did not change the ganglioside pattern of intestinal mucosa, had very little influence on the number of toxin binding sites on intestinal cells, and did not alter the sensitivity of the small bowel to the diarrheogenic action of the toxin. These results demonstrate a relationship in the intestinal mucosa between the GM1 ganglioside concentration, the number of binding sites for cholera toxin, and the sensitivity to the biologic action of the toxin. Thus, the study strongly supports the concept that the GM1 ganglioside is the intestinal binding receptor for cholera toxin.
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PMID:Interaction of cholera toxin and membrane GM1 ganglioside of small intestine. 105 71

The glycoproteins in the normal pig bronchial gland are identified by the combined Alcian Blue (AB)-periodic acid Schiff (PAS) technique, with the use of sialidase digestion and AB staining either at pH 2-6 or at pH 1-0. In enzootic pneumonia (produced experimentally by infection with Mycoplasma hyorhinis) the bronchial gland hypertrophies, mucous and serous cells both increase, in number and size; hence the total glycoprotein content of the gland increases. The distribution of glycoproteins in the hypertrophied gland differs from that in the normal. Quantitative analysis of the mucous cells shows that in the hypertrophied gland the acid glycoprotein is increased relative to the neutral. There is also a relative change in the amounts of sialidase-sensitive sialomucin and sulphomucin; both are significantly increased at the expense of the sialidase-resistant sialomucin. Qualitative analysis of the serous cells shows that in the normal gland most of the glycoprotein is neutral and that the small amount of acid glycoprotein is sialidase-resistant sialomucin. In the hypertrophied gland there is relatively more acid glycoprotein which is either sialidase-resistant sialomucin or sulphomucin; in addition, in pigs with enzootic pneumonia there is an increase in the height of the bronchial epithelium and a depletion in both goblet cell number and glycoprotein content, which latter has more neutral glycoprotein and less acid glycoprotein.
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PMID:Histochemical identification of glycoproteins in pig bronchial epithelium: (a) normal and (b) hypertrophied from enzootic pneumonia. 115 72

Certain enzyme activities for synthesis and degradation of gangliosides and the chemical quantity and incorporation of radioactivity from [14C] galactose into gangliosides have been studied in 3T3 cells and their transformed counterparts at various cell population densities. The chemical quantity of and the incorporation of radioactivity into GD1a ganglioside increased at the early stage of cell contact ("contact response" of ganglisoide), whereas response was not detectable in transformed 3T3 cells at any stage of cell contact. These phenomena were reproduced in five separate qualitative analyses and two quantitative determinations of gangliosides. As the basis of these phenomena, a membrane-bound sialidase activity which acted on gangliosides was suppressed in 3T3 cells at the "touching" stage of cell-to-cell contact. Transformed cells did not display the change of sialidase activity at any stage of cell contact.
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PMID:Cell contact-dependent ganglioside changes in mouse 3T3 gibroblasts and a suppressed sialidase activity on cell contact. 117 Aug 79

Some strains of Sporothrix schenckii and one strain of Ceratocystis stenoceras were investigated and the occurrence of the enzyme neuraminidase (= sialidase, N-acetylneuraminate glycohydrolase, EC 3.2.1.18) was proved not only by Warren's thiobarbituric acid assay but also by immunoelectrophoresis technique using monospecific antisera against 25 human glycoproteins, lipoproteins, immunoglobulins, fibrinogen and some other proteins (Table 1). There are also fibrinolytic and lipolytic enzyme activities in strains of Sporothrix chenckii corresponding with similar findings of other authors and also in the Ceratocystis stenoceras strain. The temperature optimum of production of neuraminidase seems to be lower than 37 degrees C (Table 2) and all strains failed to produce the enzyme after cultivation at 37 degrees C during some months. The findings of the existence of neuraminidase in the both species confirm also their close relationship. Because the occurrence of N-acylneuraminate was shown only in animals and in some microorganisms but not in plants it can be suggested that also Sporothrix schenckii and Ceratocystis stenoceras grow on animal or neuraminate containing microbial material but not on plants as it is assumed hitherto. Corresponding to this hypothesis the pathogenicity of Sporothrix schenckii and also the facultative pathogenicity of Ceratocystis stenoceras are to see in connexion with the action of neuraminidase and other enzymes metabolizing animal substrates. It can be concluded that neuraminidase is a possible additional pathogenic factor in sporotrichosis below 37 degrees C.
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PMID:[Occurrence of neuraminidase in Sporothrix schenckii and Ceratocystis stenoceras and its role in ecology and pathomechanism of these fungi (author's transl)]. 117 86


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