THE EFFECTS OF SIALIDASE ON PSEUDOCHOLINESTERASE TYPES

1963 ◽  
Vol 41 (1) ◽  
pp. 969-974 ◽  
Author(s):  
D. J. Ecobichon ◽  
W. Kalow

Hereditary variants of human serum cholinesterase were exposed to the action of sialidase. The removal of the sialic acid residues had no effect on the kinetic properties of the esterases but greatly affected the electrophoretic mobility. In starch gel, there were no differences between the pseudocholinesterase types whether sialidase-treated or untreated. This observation permits two conclusions: first, the differences between the esterase types must reside in the protein cores, and second, the different variants must possess equal amounts of sialic acid per protein molecule. According to Liddell et al. there is a charge difference between esterase molecules of different type; since this cannot be accounted for by sialic acid content, the distinguishing characteristics are likely due to differences of amino acid composition.

1963 ◽  
Vol 41 (4) ◽  
pp. 969-974 ◽  
Author(s):  
D. J. Ecobichon ◽  
W. Kalow

Hereditary variants of human serum cholinesterase were exposed to the action of sialidase. The removal of the sialic acid residues had no effect on the kinetic properties of the esterases but greatly affected the electrophoretic mobility. In starch gel, there were no differences between the pseudocholinesterase types whether sialidase-treated or untreated. This observation permits two conclusions: first, the differences between the esterase types must reside in the protein cores, and second, the different variants must possess equal amounts of sialic acid per protein molecule. According to Liddell et al. there is a charge difference between esterase molecules of different type; since this cannot be accounted for by sialic acid content, the distinguishing characteristics are likely due to differences of amino acid composition.


1967 ◽  
Vol 45 (6) ◽  
pp. 1205-1210 ◽  
Author(s):  
B. E. Baker ◽  
V. B. Hatcher ◽  
C. R. Harington

Polar bear milk was stored in the frozen state for 2 months. It was then thawed and subjected to low-speed centrifugation. The material (D) which deposited at the bottom of the centrifuge tube and also the casein and whey proteins isolated from the supernate were analyzed by polyacrylamide-gel (without urea) electrophoresis. The precipitate (D) and the casein gave closely similar electrophoretic patterns. However, the precipitate (D) contained less than 20% of the carbohydrate (hexose, hexosamine, sialic acid) content of the casein. Polar bear casein and bovine casein gave similar electropherograms when subjected to polyacrylamide-gel (7 M urea) electrophoretic analysis. Human casein gave eight distinct bands, four of which had higher mobilities than did bovine αs-casein. Starch-gel (2-mercaptoethanol added) electrophoretic analysis indicated that polar bear casein and human casein produced 8 and 13 electrophoretic components respectively.


1975 ◽  
Vol 145 (2) ◽  
pp. 401-403 ◽  
Author(s):  
J C Londesborough ◽  
U Hamberg

The sialic acid content of highly purified human kininogen was found to be about 8.6 mol/mol(mol.wt. 50,000). The isoelectric point (pH 4.9 +/- 0.2) is much higher than that of bovine low-molecular-weight kininogen, but is close to that expected from the amino acid and sialic acid analyses.


1971 ◽  
Vol 123 (3) ◽  
pp. 399-405 ◽  
Author(s):  
J. G. Beeley

Three major and two minor species of ovomucoid were separated by chromatography on sulphoethyl-Sephadex. The predominant sialic acid-free species was further resolved into three fractions by DEAE-cellulose chromatography. Although all species of ovomucoid had closely similar trypsin-inhibiting activity, immunochemical properties and amino acid composition, they differ in carbohydrate composition. Wide variation was observed in the content of galactose, N-acetylglucosamine and sialic acid. Charge heterogeneity was related, in part, to variation in sialic acid content. The implications of variable carbohydrate composition for the structure and function of ovomucoid are discussed.


2007 ◽  
Vol 177 (4S) ◽  
pp. 44-45
Author(s):  
C. Lowell Parsons ◽  
Mahadevan Rajasekaran ◽  
Marianne Chenoweth ◽  
Paul Stein

1978 ◽  
Vol 41 (1) ◽  
pp. 175-178 ◽  
Author(s):  
J. Morser ◽  
J. P. Kabayo ◽  
D. W. Hutchinson

1994 ◽  
Vol 180 (6) ◽  
pp. 2137-2145 ◽  
Author(s):  
M S Villanueva ◽  
C J Beckers ◽  
E G Pamer

Listeria monocytogenes is a facultative intracellular bacterium that causes severe disease in neonates and immunocompromised adults. Although entry, multiplication, and locomotion of Listeria in the cytosol of infected cells are well described, the impact of such infection on the host cell is unknown. In this report, we investigate the effect of L. monocytogenes infection on MHC class I synthesis, processing, and intracellular trafficking. We show that L. monocytogenes infection interferes with normal processing of N-linked oligosaccharides on the major histocompatibility complex (MHC) class I heavy chain molecule, H-2Kd, resulting in a reduced sialic acid content. The glycosylation defect is more pronounced as the infection progresses and results from interference with the addition of sialic acid rather than its removal by a neuraminidase. The effect is found in two different cell lines and is not limited to MHC class I molecules since CD45, a surface glycoprotein, and LGP120, a lysosomal glycoprotein, are similarly affected by L. monocytogenes infection. The glycosylation defect is specific for infection by L. monocytogenes since neither Trypanosoma cruzi nor Yersinia enterocolitica, two other intracellular pathogens, reproduces the effect. The resultant hyposialylation of H-2Kd does not impair its surface expression in infected cells. Diminished sialic acid content of surface glycoproteins may enhance host-defense by increasing susceptibility to lysis and promoting clearance of Listeria-infected cells.


2012 ◽  
Vol 32 (3) ◽  
pp. 179-186 ◽  
Author(s):  
Mohammad Murtaza Mehdi ◽  
Prabhakar Singh ◽  
Syed Ibrahim Rizvi

Sialic acids are substituted neuraminic acid derivatives which are typically found at the outermost end of glycan chains on the membrane in all cell types. The role of erythrocyte membrane sialic acids during aging has been established however the relationship between sialic acid and oxidative stress is not fully understood. The present work was undertaken to analyze the relationship between erythrocyte membrane sialic acid with its plasma level, membrane and plasma lipid hydroperoxide levels and plasma total antioxidant capacity. Results show that sialic acid content decreases significantly (P< 0.001) in RBC membrane (r= −0.901) and increases in plasma (r= 0.860) as a function of age in humans. Lipid peroxidation measured in the form of hydroperoxides increases significantly (P< 0.001) in plasma (r= 0.830) and RBC membranes (r= 0.875) with age in humans. The Trolox Equivalent Total Antioxidant Capacity (TETAC) of plasma was found to be significantly decreased (P< 0.001,r= −0.844). We observe significant correlations between decrease of erythrocyte membrane sialic acid and plasma lipid hydroperoxide and TETAC. Based on the observed correlations, we hypothesize that increase in oxidative stress during aging may influence the sialic acid decomposition from membrane thereby altering the membrane configuration affecting many enzymatic and transporter activities. Considering the importance of plasma sialic acid as a diagnostic parameter, it is important to establish age-dependent reference.


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