scholarly journals Elucidation of the topological parameters of N-acetylneuraminic acid and some analogues involved in their interaction with the N-acetylneuraminate lyase from Clostridium perfringens

1992 ◽  
Vol 282 (2) ◽  
pp. 511-516 ◽  
Author(s):  
E Zbiral ◽  
R G Kleineidam ◽  
E Schreiner ◽  
M Hartmann ◽  
R Christian ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Oxygen Atom ◽  
Clostridium Perfringens ◽  
Pyruvic Acid ◽  
Sialic Acids ◽  
Side Chain ◽  
Equatorial Zone ◽  
Enzyme Action ◽  
Acetylneuraminic Acid ◽  
Topological Parameters

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.

Sialic Acid (N-Acetylneuraminic Acid) in Human Serum

1964 ◽  
Vol 10 (11) ◽  
pp. 986-990 ◽  
Author(s):  
J A Cabezas ◽  
J Vazquez Porto
Keyword(s):  
Sialic Acid ◽  
Rheumatic Disease ◽  
Human Serum ◽  
Spectrophotometric Method ◽  
Butyl Acetate ◽  
Normal Values ◽  
Sialic Acids ◽  
Old Adults ◽  
Acetylneuraminic Acid ◽  
Severe Burns

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.

Glycoengineering the N-acyl side chain of sialic acid of human erythropoietin affects its resistance to sialidase

2012 ◽  
Vol 393 (8) ◽  
pp. 777-783 ◽  
Author(s):  
Anselm Werner ◽  
Rüdiger Horstkorte ◽  
Dagobert Glanz ◽  
Karina Biskup ◽  
Véronique Blanchard ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Culture Medium ◽  
Sialic Acids ◽  
Side Chain ◽  
Cell Culture Medium ◽  
Terminal Position ◽  
Human Erythropoietin ◽  
Recombinant Glycoproteins ◽  
Complex Glycans ◽  
Over Time

Abstract During the last years, the use of therapeutic glycoproteins has increased strikingly. Glycosylation of recombinant glycoproteins is of major importance in biotechnology, as the glycan composition of recombinant glycoproteins impacts their pharmacological properties. The terminal position of N-linked complex glycans in mammals is typically occupied by sialic acid. The presence of sialic acid is crucial for functionality and affects the half-life of glycoproteins. However, glycoproteins in the bloodstream become desialylated over time and are recognized by the asialoglycoprotein receptors via the exposed galactose and targeted for degradation. Non-natural sialic acid precursors can be used to engineer the glycosylation side chains by biochemically introducing new non-natural terminal sialic acids. Previously, we demonstrated that the physiological precursor of sialic acid (i.e., N-acetylmannosamine) can be substituted by the non-natural precursors N-propanoylmannosamine (ManNProp) or N-pentanoylmannosamine (ManNPent) by their simple application to the cell culture medium. Here, we analyzed the glycosylation of erythropoietin (EPO). By feeding cells with ManNProp or ManNPent, we were able to incorporate N-propanoyl or N-pentanoyl sialic acid in significant amounts into EPO. Using a degradation assay with sialidase, we observed a higher resistance of EPO to sialidase after incorporation of N-propanoyl or N-pentanoyl sialic acid.

scholarly journals Sialic acid acquisition in bacteria–one substrate, many transporters

2016 ◽  
Vol 44 (3) ◽  
pp. 760-765 ◽  
Author(s):  
Gavin H. Thomas
Keyword(s):  
Sialic Acid ◽  
Immune Evasion ◽  
Sialic Acids ◽  
Major Facilitator Superfamily ◽  
Acid Uptake ◽  
Gram Negative Bacteria ◽  
Acetylneuraminic Acid ◽  
Wide Range ◽  
Major Facilitator

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.

A method for the simultaneous estimation of free and ketosidically bound sialic acids

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
Keyword(s):  
Sialic Acid ◽  
Room Temperature ◽  
Thiobarbituric Acid ◽  
Sialic Acids ◽  
Simultaneous Estimation ◽  
Sodium Metaperiodate ◽  
Acetylneuraminic Acid ◽  
Acid Reagent ◽  
Bovine Submaxillary Mucin ◽  
Free Sialic Acid

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.

The Inhibitory Effect of Sialic Acid on Fibrinolysis

1967 ◽  
Vol 17 (01/02) ◽  
pp. 023-030 ◽  
Author(s):  
H Rubin ◽  
N. D Ritz
Keyword(s):  
Sialic Acid ◽  
Inhibitory Effect ◽  
Sialic Acids ◽  
Normal Serum ◽  
The Body ◽  
Inhibitory Effects ◽  
Acetylneuraminic Acid ◽  
Heated Plates ◽  
Hydrolysis Of ◽  
Fibrinolytic Action

SummaryThe inhibitory effect of N-acetylneuraminic acid and glycolyl neuramaminic acids on the hydrolysis of 51Cr tagged casein by plasmin and α-chymotrypsin has been demonstrated. N,O-diacetylneuraminic acid was ineffective. The inhibitory effect was increased by an increase in ionic strength of the reaction mixture. The two active sialic acids also inhibited the fibrinolytic action of human plasmin on heated and unheated bovine fibrin plates. The greater inhibition noted on heated plates may indicate a primary effect on plasmin rather than on activators of plasmin. The inhibitory effects of N-acetyl neuraminic acid appeared to be potentiated by normal serum inhibitors. Sialic acid did not influence the conversion of fibrin monomer to polymer.N-acetylneuraminic acid may play an important role in preserving the integrity of fibrin deposits in the body.

Evaluation of 1,10-Phenanthroline as a Reagent for Sialic Acid Determinations

1974 ◽  
Vol 20 (3) ◽  
pp. 387-388 ◽  
Author(s):  
S L Snyder ◽  
N S Mathewson ◽  
P Z Sobocinski
Keyword(s):  
Sialic Acid ◽  
Complex Formation ◽  
Sialic Acids ◽  
Previous Investigator ◽  
Acetylneuraminic Acid ◽  
Specific Reagent

Abstract Use of o-phenanthroline as a reagent for determination of sialic acids was proposed by a previous investigator. This method was based on an increase in absorbance at 307 nm that occurred when solutions of o-phenanthroline and various sialic acids were mixed. It was postulated that the increased absorbance was a result of formation of specific complexes. Using N-acetylneuraminic acid, we found no evidence for complex formation. Our results indicate that the observations of the previous investigator resulted from shifts in the pH of the medium rather than from formation of specific complexes. Therefore o-phenanthroline is not a specific reagent for sialic acids and its use is not recommended.

scholarly journals α2,3 linkage of sialic acid to a GPI anchor and an unpredicted GPI attachment site in human prion protein

2020 ◽  
Vol 295 (22) ◽  
pp. 7789-7798 ◽  
Author(s):  
Atsushi Kobayashi ◽  
Tetsuya Hirata ◽  
Takashi Nishikaze ◽  
Akinori Ninomiya ◽  
Yuta Maki ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Prion Protein ◽  
Prion Diseases ◽  
Attachment Site ◽  
Cellular Prion Protein ◽  
Side Chain ◽  
Glycan Structure ◽  
Gpi Anchor ◽  
Acetylneuraminic Acid ◽  
Sialic Acid Linkage

Prion diseases are transmissible, lethal neurodegenerative disorders caused by accumulation of the aggregated scrapie form of the prion protein (PrPSc) after conversion of the cellular prion protein (PrPC). The glycosylphosphatidylinositol (GPI) anchor of PrPC is involved in prion disease pathogenesis, and especially sialic acid in a GPI side chain reportedly affects PrPC conversion. Thus, it is important to define the location and structure of the GPI anchor in human PrPC. Moreover, the sialic acid linkage type in the GPI side chain has not been determined for any GPI-anchored protein. Here we report GPI glycan structures of human PrPC isolated from human brains and from brains of a knock-in mouse model in which the mouse prion protein (Prnp) gene was replaced with the human PRNP gene. LC–electrospray ionization–MS analysis of human PrPC from both biological sources indicated that Gly229 is the ω site in PrPC to which GPI is attached. Gly229 in human PrPC does not correspond to Ser231, the previously reported ω site of Syrian hamster PrPC. We found that ∼41% and 28% of GPI anchors in human PrPCs from human and knock-in mouse brains, respectively, have N-acetylneuraminic acid in the side chain. Using a sialic acid linkage-specific alkylamidation method to discriminate α2,3 linkage from α2,6 linkage, we found that N-acetylneuraminic acid in PrPC's GPI side chain is linked to galactose through an α2,3 linkage. In summary, we report the GPI glycan structure of human PrPC, including the ω-site amino acid for GPI attachment and the sialic acid linkage type.

Removal of O-acetylated sialic acids from rat colonic epithelial glycoproteins by cell-free extracts of rat faeces

1983 ◽  
Vol 61 (8) ◽  
pp. 868-874 ◽  
Author(s):  
H. Poon ◽  
P. E. Reid ◽  
C. W. Ramey ◽  
W. L. Dunn ◽  
M. G. Clay
Keyword(s):  
Sialic Acid ◽  
Acid Content ◽  
Minimal Medium ◽  
Wistar Rat ◽  
Sialic Acids ◽  
Side Chain ◽  
Sialic Acid Content ◽  
Vibrio Cholera ◽  
Sterile Cell

Sterile, cell-free, extracts of freshly defaecated Wistar rat faeces in a pH 7.0 "minimal medium" contain neuraminidase(s), capable of removing sialic acids both with and without side-chain substituents from bovine submandibular mucin and rat colonic epithelial glycoproteins, and an esterase which removes O-acetyl substituents from the side chain of sialic acid residues. Studies of the removal of sialic acids from bovine submandibular mucin and rat colonic epithelial glycoproteins indicated that (i) the faecal enzymes removed a greater proportion of the sialic acid of both the de-O-acetylated and native glycoproteins than was removed with Vibrio cholera neuraminidase, (ii) sialic acids were removed more rapidly from de-O-acetylated glycoproteins, and (iii) the resistance to removal of sialic acids was apparently dependent at least in part upon the O-acetyl sialic acid content of the substrate.

Sialoglycoproteins and sialic acids ofPlasmodium knowlesischizont-infected erythrocytes and normal rhesus monkey erythrocytes

Parasitology ◽  
1986 ◽  
Vol 92 (3) ◽  
pp. 527-543 ◽  
Author(s):  
R. J. Howard ◽  
G. Reuter ◽  
J. W. Barnwell ◽  
R. Schauer
Keyword(s):  
Sialic Acid ◽  
Rhesus Monkey ◽  
Acid Content ◽  
Sialic Acids ◽  
Galactose Oxidase ◽  
Parasite Development ◽  
Sialic Acid Content ◽  
Acetylneuraminic Acid ◽  
Total Sialic Acid ◽  
Significant Difference

SUMMARYThe effects of malaria infection on RBC sialic acids and sialoglycoproteins were studied with asexual blood-stage infections ofPlasmodium knowlesiin rhesus monkeys. Glycoprotein radio-isotope labelling methods were used to compare the sialoglycoproteins of normal RBC andP. knowlesischizont-infected RBC (SI-RBC). Tritiation of glycoproteins from SI-RBC with the standard sialidase + galactose oxidase/NaB3H4method or standard periodate/NaB3H4method was significantly decreased when compared to normal RBC. However, tritium uptake into glycoproteins was normal when SI-RBC were treated with 5-fold higher concentrations of both enzymes in the first labelling method, or with a 5-fold increase in the molar ratio of periodate to sialic acid in the second method. The mobility of tritiated host cell glycoproteins on SDS–polyacrylamide gels was identical for SI-RBC and normal RBC. New bands, possibly glycoproteins, of 230, 160, 90, 52, and 30 kDa were detected after labelling SI-RBC by the modified periodate/NaB3H4method. Sialic acid analysis of normal rhesus monkey RBC (62μg/1010RBC) revealed that 46% of the total sialic acid wasN-glycolylneuraminic acid, 33% wasN-acetyl-9-O-acetylneuraminic acid, and the remainderN-acetylneuraminic acid. SI-RBC collected either directly from infected monkeys or afterin vitroculture of ring-infected RBC in horse serum, had increased total sialic acid (126 or 115μg/1010RBC, respectively). The sialic acid content of infected RBC must increase during parasite development since RBC infected with ring-stageP. knowlesihad the same content as normal RBC. There was no significant difference in the ratio of the three sialic acids of SI-RBC and normal RBC. In contrast, the uninfected RBC from infected blood of different monkeys showed marked variation in sialic acid composition and generally had a lower sialic acid content than normal RBC.

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
Keyword(s):  
Sialic Acid ◽  
Antigenic Determinant ◽  
Human Liver ◽  
Competitive Ability ◽  
Sialic Acids ◽  
Acetylneuraminic Acid ◽  
Colominic Acid ◽  
Sugar Derivatives ◽  
Radioimmunoassay Method

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.

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