scholarly journals Radioimmunochemical evidence for a role of carbohydrate in antigenic determinant(s) on human liver α-L-fucosidase

1984 ◽  
Vol 223 (2) ◽  
pp. 293-298 ◽  
Author(s):  
J A Alhadeff ◽  
G L Andrews-Smith

A competitive-binding radioimmunoassay method was employed to investigate the role of carbohydrate in antigenic determinant(s) of human liver alpha-L-fucosidase. Competition curves were used to quantify the concentrations of competitors needed to cause 30% inhibition of the precipitation of 125I-labelled alpha-L-fucosidase. The isoelectric forms of alpha-L-fucosidase, which are related by sialic acid residues, were separated preparatively and used as competitors in the radioimmunoassay. A pattern of increasing effectiveness as competitors with increasing acidity of the forms was found, suggesting that sialic acid may be involved in the antigenic determinant(s) of alpha-L-fucosidase. Specificity was exhibited when sugar and sugar derivatives were used as competitors in the radioimmunoassay: a 51-fold range of competitive ability was found, and sialic acids (N-acetylneuraminic acid and N-glycollylneuraminic acid) and colominic acid (a polymer of N-acetylneuraminic acid) were the best competitors. The results of our studies suggest that carbohydrate contributes to antigenic determinant(s) of alpha-L-fucosidase and that sialic acid is probably the major sugar involved.

1964 ◽  
Vol 10 (11) ◽  
pp. 986-990 ◽  
Author(s):  
J A Cabezas ◽  
J Vazquez Porto

Abstract A simple spectrophotometric method is described for the sialic acids which utilizes the reaction with resorcinol and extraction with butyl acetate-n-butanol as a solvent. Normal values for adults, utilizing N-acetylneuraminic acid as a standard, were found to be 60 ± 10.4 mg./100 ml. Values for newborn babies averaged 40.4 ± 5.7. Similar values were found for specimens from 2-month-old infants to 27-year-old adults. Higher values were noted in the case of rickets, severe burns, rheumatic disease, and tuberculosis.


Author(s):  
Selma Süer Gökmen ◽  
Cemal Kazezoğlu ◽  
Bendigar Sunar ◽  
Fatih Özçelik ◽  
Özgül Güngör ◽  
...  

AbstractThe role of sialic acid (SA) in the pathogenesis of atherosclerosis and as a predictor of cardiovascular events has attracted much attention in recent years. However, most studies investigating the role of total and lipid-bound sialic acids (TSA and LSA) in the pathogenesis of atherosclerosis lack information on the reason for the elevated SA concentrations in coronary heart disease and myocardial infarction. Since the inflammation-sensitive proteins are glycoproteins with SA residues, an increase in their levels due to some type of acute-phase reaction or inflammation could be responsible for the elevated TSA levels in acute myocardial infarction (AMI). Elevated serum SA levels might also be due to either shedding or secretion of free SA from the cell or cell membrane surface if neuraminidase levels are increased, or to the release of cellular SA-containing glycolipids and/or glycoproteins into plasma from myocardial cells after AMI. The aim of the present study was to investigate both the possible role of SA-rich inflammation-sensitive proteins and the cell damage due to elevated serum TSA levels in AMI. A possible role of serum LSA as an indicator of the shedding or secretion of SA from the cell or cell membrane surface in AMI was also evaluated. The study included 38 subjects with AMI and 32 healthy volunteers. Serum TSA and LSA were determined using the methods of Warren and Katopodis, respectively. The concentrations of serum SA-rich inflammation-sensitive proteins, namely α


Author(s):  
Tainá Cavalcante ◽  
Mariana Medina Medeiros ◽  
Simon Ngao Mule ◽  
Giuseppe Palmisano ◽  
Beatriz Simonsen Stolf

Carbohydrates or glycans are ubiquitous components of the cell surface which play crucial biological and structural roles. Sialic acids (Sias) are nine-carbon atoms sugars usually present as terminal residues of glycoproteins and glycolipids on the cell surface or secreted. They have important roles in cellular communication and also in infection and survival of pathogens. More than 20 pathogens can synthesize or capture Sias from their hosts and incorporate them into their own glycoconjugates and derivatives. Sialylation of pathogens’ glycoconjugates may be crucial for survival inside the host for numerous reasons. The role of Sias in protozoa such as Trypanosoma and Leishmania was demonstrated in previous studies. This review highlights the importance of Sias in several pathogenic infections, focusing on Leishmania. We describe in detail the contributions of Sias, Siglecs (sialic acid binding Ig-like lectins) and Neuraminidase 1 (NEU 1) in the course of Leishmania infection. A detailed view on the structural and functional diversity of Leishmania-related Sias and host-cell receptors will be provided, as well as the results of functional studies performed with different Leishmania species.


2016 ◽  
Vol 44 (3) ◽  
pp. 760-765 ◽  
Author(s):  
Gavin H. Thomas

The sialic acids are a family of 9-carbon sugar acids found predominantly on the cell-surface glycans of humans and other animals within the Deuterostomes and are also used in the biology of a wide range of bacteria that often live in association with these animals. For many bacteria sialic acids are simply a convenient source of food, whereas for some pathogens they are also used in immune evasion strategies. Many bacteria that use sialic acids derive them from the environment and so are dependent on sialic acid uptake. In this mini-review I will describe the discovery and characterization of bacterial sialic acids transporters, revealing that they have evolved multiple times across multiple diverse families of transporters, including the ATP-binding cassette (ABC), tripartite ATP-independent periplasmic (TRAP), major facilitator superfamily (MFS) and sodium solute symporter (SSS) transporter families. In addition there is evidence for protein-mediated transport of sialic acids across the outer membrane of Gram negative bacteria, which can be coupled to periplasmic processing of different sialic acids to the most common form, β-D-N-acetylneuraminic acid (Neu5Ac) that is most frequently taken up into the cell.


FEBS Letters ◽  
1989 ◽  
Vol 250 (2) ◽  
pp. 429-432 ◽  
Author(s):  
Camino González-Clemente ◽  
José M. Luengo ◽  
Leandro B. Rodríguez-Aparicio ◽  
Angel Reglero

Parasitology ◽  
2008 ◽  
Vol 136 (2) ◽  
pp. 159-173 ◽  
Author(s):  
A. GHOSHAL ◽  
S. MUKHOPADHYAY ◽  
A. K. CHAVA ◽  
G. J. GERWIG ◽  
J. P. KAMERLING ◽  
...  

SUMMARYDistribution of 9-O-acetylated sialic acids (9-O-AcSA) onLeishmania donovanihas been previously reported. Considering their role in recognition, the differential distribution of sialic acids especially 9-O-acetylated sialic acids in avirulent (UR6) versus virulent (AG83 and GE1) promastigotes ofLeishmania donovaniand its role in entry into macrophages was explored. Fluorimetric-HPLC, fluorimetric determination and ELISA revealed 14-, 8- and 5-fold lower sialic acids in UR6 as compared to AG83. Interestingly, on UR6, flow cytometry indicated lower (α2→6)-linked sialoglycoproteins along with minimal 9-O-acetylated sialoglycoproteins by Scatchard analysis. Further, UR6 demonstrated a 9- and 14·5-fold lower infectivity and phagocytic index than AG83. Additionally, de-O-acetylation and de-sialylation of AG83 demonstrated a 3- and 1·5-fold reduced phagocytic index. The role of 9-O-AcSA in entry was further confirmed by pre-blocking the macrophage surface with a cocktail of sugars followed by microscopic quantification. The phagocytic index of AG83 exclusively through 9-O-AcSA was significantly high. Interestingly, AG83 produced higher metacyclic promastigotes containing increased 9-O-AcSA as compared to avirulent UR6 supporting its virulent nature. Taken together; our results conclusively demonstrate the increased presence of 9-O-acetylated sialic acid on promastigotes of virulentLeishmania donovanias compared to avirulent UR6 and their subsequent role in entry within macrophages.


1992 ◽  
Vol 282 (2) ◽  
pp. 511-516 ◽  
Author(s):  
E Zbiral ◽  
R G Kleineidam ◽  
E Schreiner ◽  
M Hartmann ◽  
R Christian ◽  
...  

A series of neuraminic acid derivatives modified in the side chain or at C-3, C-4 or C-5 were tested as substrates of inhibitors of N-acetylneuraminate lyase (EC 4.1.3.3) from Clostridium perfringens. The results, together with Km and Ki values reported previously, indicate that the region most important for the binding of sialic acids is an equatorial zone reaching from C-8 via the ring oxygen atom to C-4 of the sugar molecule, whereas the substituents at C-9 and C-5 may be varied to a higher extent without significantly disturbing enzyme action. It is shown that stereo-electronic factors are responsible for the immediate heterolytic fragmentation of the cyclic sialic acid into pyruvic acid and 2-acetamidomannose or a related C-6 sugar.


2000 ◽  
Vol 74 (24) ◽  
pp. 11825-11831 ◽  
Author(s):  
Yasuo Suzuki ◽  
Toshihiro Ito ◽  
Takashi Suzuki ◽  
Robert E. Holland ◽  
Thomas M. Chambers ◽  
...  

ABSTRACT The distribution of sialic acid (SA) species varies among animal species, but the biological role of this variation is largely unknown. Influenza viruses differ in their ability to recognize SA-galactose (Gal) linkages, depending on the animal hosts from which they are isolated. For example, human viruses preferentially recognize SA linked to Gal by the α2,6(SAα2,6Gal) linkage, while equine viruses favor SAα2,3Gal. However, whether a difference in relative abundance of specific SA species (N-acetylneuraminic acid [NeuAc] andN-glycolylneuraminic acid [NeuGc]) among different animals affects the replicative potential of influenza viruses is uncertain. We therefore examined the requirement for the hemagglutinin (HA) for support of viral replication in horses, using viruses whose HAs differ in receptor specificity. A virus with an HA recognizing NeuAcα2,6Gal but not NeuAcα2,3Gal or NeuGcα2,3Gal failed to replicate in horses, while one with an HA recognizing the NeuGcα2,3Gal moiety replicated in horses. Furthermore, biochemical and immunohistochemical analyses and a lectin-binding assay demonstrated the abundance of the NeuGcα2,3Gal moiety in epithelial cells of horse trachea, indicating that recognition of this moiety is critical for viral replication in horses. Thus, these results provide evidence of a biological effect of different SA species in different animals.


1977 ◽  
Vol 55 (7) ◽  
pp. 778-782 ◽  
Author(s):  
C. F. A. Culling ◽  
P. E. Reid ◽  
C. W. Ramey ◽  
W. L. Dunn ◽  
M. G. Clay

Various methods for the estimation of free and ketosidically bound sialic acid were investigated for accuracy and specificity. It was found that oxidation with 0.025 M sodium metaperiodate in pH 7.0 phosphate buffer at room temperature for 20 min provided a simple, rapid, sensitive method whereby both the free and the ketosidically bound acid present in a mixture could be quantitatively analyzed. On completion of the oxidation step, the bound sialic acid is estimated with resorcinol reagent and the free sialic acid with thiobarbituric acid reagent. Oxidation under these conditions permitted a facile analysis of mixtures of bovine submaxillary mucin and free N-acetylneuraminic acid, whereas the Warren thiobarbituric acid procedure gave an erroneous value for free sialic acid.


2009 ◽  
Vol 390 (7) ◽  
Author(s):  
Stefan O. Reinke ◽  
Gerhard Lehmer ◽  
Stephan Hinderlich ◽  
Werner Reutter

AbstractThe key enzyme for the biosynthesis ofN-acetylneuraminic acid, from which all other sialic acids are formed, is the bifunctional enzyme UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE). GNE is a highly conserved protein found throughout the animal kingdom. Its highest expression is seen in the liver and placenta. GNE is regulated by a variety of biochemical means, including tetramerization promoted by the substrate UDP-GlcNAc, phosphorylation by protein kinase C and feedback inhibition by CMP-Neu5Ac, which is defect in the human disease sialuria. GNE knock-out in mice leads to embryonic lethality, emphasizing the crucial role of this key enzyme for sialic acid biosynthesis. The metabolic capacity to synthesize sialic acid and CMP-sialic acid upon ManNAc loads is amazingly high. An additional characteristic of GNE is its interaction with proteins involved in the regulation of development, which might play a crucial role in the hereditary inclusion body myopathy. Due to the importance of increased concentrations of tumor-surface sialic acid, first attempts to find inhibitors of GNE have been successful.


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