Porcine Sugar Nucleotide: Glycoprotein Glycosyltransferases. I. Blood Serum and Liver Sialyltransferase

1971 ◽  
Vol 49 (7) ◽  
pp. 829-837 ◽  
Author(s):  
Roger L. Hudgin ◽  
Harry Schachter
Keyword(s):  
Sialic Acid ◽  
High Speed ◽  
Liver Homogenate ◽  
Acetone Powder ◽  
Acid Glycoprotein ◽  
Acetylneuraminic Acid ◽  
Pork Liver ◽  
Terminal Galactose ◽  
And Function ◽  
Powder Extract

The properties of CMP-N acetylneuraminic acid: glycoprotein sialyltransferase have been studied in pork serum, a crude pork liver homogenate, and a soluble acetone powder extract prepared from pork liver. Whereas the crude liver homogenate enzyme is activated by the detergent Triton X-100, this detergent has no effect on the activities of either serum or acetone powder extract; since high-speed centrifugation does not sediment the enzyme activities of the latter two preparations, it is concluded that they are soluble. Comparison of the membrane-bound and soluble liver enzymes indicates that the membrane modifies kinetic behavior only to a limited extent. In both liver and serum, a single sialyltransferase is responsible for incorporation of sialic acid into α1-acid glycoprotein, fetuin, and N-acetyllactosamine, and sialic acid incorporation occurs whenever a terminal galactose linked (β, 1 → 4) to a penultimate N-acetylglucosamine is presented to the enzyme. Although the serum enzyme resembles the liver enzyme, both the source and function of serum sialyltransferase are unknown.

Incorporation of Sialic Acid into Sialidase-Treated Apolipoprotein of Human, Very Low Density Lipoprotein by a Pork Liver Sialyltransferase

1974 ◽  
Vol 52 (8) ◽  
pp. 655-664 ◽  
Author(s):  
Stephen Wetmore ◽  
Robert W. Mahley ◽  
W. Virgil Brown ◽  
Harry Schachter
Keyword(s):  
Low Density Lipoprotein ◽  
Liver Microsomes ◽  
Density Lipoprotein ◽  
Very Low Density Lipoprotein ◽  
Low Density ◽  
Ph Optimum ◽  
Acetylneuraminic Acid ◽  
Pork Liver ◽  
Terminal Galactose ◽  
Ovine Submaxillary Mucin

Pork liver microsomes are capable of catalyzing the incorporation of N-14C-acetylneuraminic acid from CMP-N-14C-acetylneuraminic acid into a sialidase-treated apolipoprotein (apoLP-Ala1) prepared from human, very low density lipoprotein and into sialidase-treated ovine submaxillary mucin. The pH optimum for the lipoprotein sialyltransferase is 5.8, and the Km values for CMP-N-acetylneuraminic acid, sialidase-treated apoLP-Ala1 and sialidase-treated ovine submaxillary mucin are, respectively, 0.04 mM, 0.04 mM, and 10 mM. Mixed substrate experiments indicate that the same sialyltransferase acts on both lipoprotein and mucin acceptors but that this enzyme is different from a previously described pork liver sialyltransferase which incorporates N-acetylneuraminic acid into linkage with the terminal galactose residues of sialidase-treated α1-acid glycoprotein. The radioactive product of the lipoprotein sialyltransferase releases, on treatment with alkaline borohydride, a reduced oligosaccharide tentatively identified as N-14C-acetylneuraminyl-N-acetylgalactosaminitol.

scholarly journals Studies on the carbohydrate moiety of α1-acid glycoprotein (orosomucoid) by using alkaline hydrolysis and deamination by nitrous acid

1971 ◽  
Vol 124 (3) ◽  
pp. 591-604 ◽  
Author(s):  
M. Isemura ◽  
K. Schmid
Keyword(s):  
Sialic Acid ◽  
Acid Hydrolysis ◽  
Alkaline Hydrolysis ◽  
Nitrous Acid ◽  
Rapid Determination ◽  
Carbohydrate Moiety ◽  
Gas Liquid Chromatography ◽  
Acid Glycoprotein ◽  
Acetylneuraminic Acid ◽  
First Time

Alkaline hydrolysis followed by deamination with nitrous acid was applied for the first time to a glycoprotein, human plasma α1-acid glycoprotein (orosomucoid). This procedure, which specifically cleaves the glycosaminidic bonds, yielded well-defined oligosaccharides. The trisaccharides, which were obtained from the native protein, consisted of a sialic acid derivative, galactose and 2,5-anhydromannose. The linkage between galactose and 2,5-anhydromannose is most probably a (1→4)-glycosidic bond. A hitherto unknown linkage between N-acetylneuraminic acid and galactose was also established, namely a (2→2)-linkage. The three linkages between sialic acid and galactose described in this paper appear to be about equally resistant to mild acid hydrolysis. The disaccharide that was derived from the desialized glycoprotein consisted of galactose and 2,5-anhydromannose. Evidence was obtained for the presence of a new terminal sialyl→N-acetylglucosamine disaccharide accounting for approximately 1mol/mol of protein. The presence of this disaccharide may explain the relatively severe requirements for the complete acid hydrolysis of the sialyl residues. The present study indicates that alkaline hydrolysis followed by nitrous acid deamination in conjunction with gas–liquid chromatography will afford relatively rapid determination of the partial structure of the complex carbohydrate moiety of glycoproteins.

scholarly journals Sialic Acid—Modified Nanoparticles—New Approaches in the Glioma Management—Perspective Review

2021 ◽  
Vol 22 (14) ◽  
pp. 7494
Author(s):  
Przemyslaw Wielgat ◽  
Katarzyna Niemirowicz-Laskowska ◽  
Agnieszka Z. Wilczewska ◽  
Halina Car
Keyword(s):  
Sialic Acid ◽  
Clinical Observation ◽  
Malignant Cell ◽  
Cellular Heterogeneity ◽  
Molecular Processes ◽  
Management Perspective ◽  
Therapeutic Tools ◽  
And Function ◽  
Worse Prognosis

The cell surface is covered by a dense and complex network of glycans attached to the membrane proteins and lipids. In gliomas, the aberrant sialylation, as the final stage of glycosylation, is an important regulatory mechanism of malignant cell behavior and correlates with worse prognosis. Better understanding of the role of sialylation in cellular and molecular processes opens a new way in the development of therapeutic tools for human brain tumors. According to the recent clinical observation, the cellular heterogeneity, activity of brain cancer stem cells (BCSCs), immune evasion, and function of the blood–brain barrier (BBB) are attractive targets for new therapeutic strategies. In this review, we summarize the importance of sialic acid-modified nanoparticles in brain tumor progression.

scholarly journals The fate of orally administered sialic acid: First insights from patients with N-acetylneuraminic acid synthase deficiency and control subjects

2021 ◽  
Vol 28 ◽  
pp. 100777
Author(s):  
Christel Tran ◽  
Licia Turolla ◽  
Diana Ballhausen ◽  
Sandrine Cornaz Buros ◽  
Tony Teav ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Acetylneuraminic Acid ◽  
Control Subjects ◽  
And Control

scholarly journals Detection of CMP-N-acetylneuraminic acid hydroxylase activity in fractionated mouse liver

1989 ◽  
Vol 263 (2) ◽  
pp. 355-363 ◽  
Author(s):  
L Shaw ◽  
R Schauer
Keyword(s):  
Submandibular Gland ◽  
Mouse Liver ◽  
High Speed ◽  
Metal Salts ◽  
Supernatant Fraction ◽  
Inhibitory Influence ◽  
Hydroxylase Activity ◽  
Acetylneuraminic Acid ◽  
Liver Homogenates ◽  
High Speed Supernatant

The finding that N-glycoloylneuraminic acid (Neu5Gc) in pig submandibular gland is synthesized by hydroxylation of the sugar nucleotide CMP-Neu5Ac [Shaw & Schauer (1988) Biol. Chem. Hoppe-Seyler 369, 477-486] prompted us to investigate further the biosynthesis of this sialic acid in mouse liver. Free [14C]Neu5Ac, CMP-[14C]Neu5Ac and [14C]Neu5Ac glycosidically bound by Gal alpha 2-3- and Gal alpha 2-6-GlcNAc beta 1-4 linkages to fetuin were employed as potential substrates in experiments with fractionated mouse liver homogenates. The only substrate to be hydroxylated was the CMP-Neu5Ac glycoside. The product of the reaction was identified by chemical and enzymic methods as CMP-Neu5Gc. All of the CMP-Neu5Ac hydroxylase activity was detected in the high-speed supernatant fraction. The hydroxylase required a reduced nicotinamide nucleotide [NAD(P)H] coenzyme and molecular oxygen for activity. Furthermore, the activity of this enzyme was enhanced by exogenously added Fe2+ or Fe3+ ions, all other metal salts tested having a negligible or inhibitory influence. This hydroxylase is therefore tentatively classified as a monooxygenase. The cofactor requirement and CMP-Neu5Ac substrate specificity are identical to those of the enzyme in high-speed supernatants of pig submandibular gland, suggesting that this is a common route of Neu5Gc biosynthesis. The relevance of these results to the regulation of Neu5Gc expression in sialoglycoconjugates is discussed.

scholarly journals N-Glycolylneuraminic Acid in Animal Models for Human Influenza A Virus

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 815
Author(s):  
Cindy M. Spruit ◽  
Nikoloz Nemanichvili ◽  
Masatoshi Okamatsu ◽  
Hiromu Takematsu ◽  
Geert-Jan Boons ◽  
...  
Keyword(s):  
Sialic Acid ◽  
Animal Models ◽  
Influenza A ◽  
Influenza Virus Infection ◽  
Influenza Viruses ◽  
Upper Respiratory Tract ◽  
Human Influenza ◽  
Influenza A Viruses ◽  
Sialic Acid Content ◽  
Acetylneuraminic Acid

The first step in influenza virus infection is the binding of hemagglutinin to sialic acid-containing glycans present on the cell surface. Over 50 different sialic acid modifications are known, of which N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc) are the two main species. Animal models with α2,6 linked Neu5Ac in the upper respiratory tract, similar to humans, are preferred to enable and mimic infection with unadapted human influenza A viruses. Animal models that are currently most often used to study human influenza are mice and ferrets. Additionally, guinea pigs, cotton rats, Syrian hamsters, tree shrews, domestic swine, and non-human primates (macaques and marmosets) are discussed. The presence of NeuGc and the distribution of sialic acid linkages in the most commonly used models is summarized and experimentally determined. We also evaluated the role of Neu5Gc in infection using Neu5Gc binding viruses and cytidine monophosphate-N-acetylneuraminic acid hydroxylase (CMAH)-/- knockout mice, which lack Neu5Gc and concluded that Neu5Gc is unlikely to be a decoy receptor. This article provides a base for choosing an appropriate animal model. Although mice are one of the most favored models, they are hardly naturally susceptible to infection with human influenza viruses, possibly because they express mainly α2,3 linked sialic acids with both Neu5Ac and Neu5Gc modifications. We suggest using ferrets, which resemble humans closely in the sialic acid content, both in the linkages and the lack of Neu5Gc, lung organization, susceptibility, and disease pathogenesis.

Interaction of Mycoplasma gallisepticum with sialyl glycoproteins

1980 ◽  
Vol 30 (2) ◽  
pp. 353-361
Author(s):  
L R Glasgow ◽  
R L Hill
Keyword(s):  
Sialic Acid ◽  
Mycoplasma Gallisepticum ◽  
Binding Assays ◽  
Molecular Weights ◽  
Acetylneuraminic Acid ◽  
Direct Binding ◽  
Membrane Bound ◽  
Strict Specificity ◽  
Human Glycophorin ◽  
Acid Structure

The binding of several glycoproteins to freshly grown and harvested cells of Mycoplasma gallisepticum was examined. Only human glycophorin, the major sialoglycoprotein of the erythrocyte membrane, bound tightly as judged by direct binding assays with 125I-labeled glycoproteins. Neuraminidase-treated glycophorin did not bind, suggesting that binding is mediated through sialic acid groups. Although other sialoglycoproteins did not appear to bind M. gallisepticum by direct binding assays, some inhibited the binding of glycophorin. The best inhibitors had a mucin-like structure, with high molecular weights and high sialic acid contents. N-acetylneuraminic acid appeared to be the favored sialic acid structure for binding, but there was no strict specificity for its anomeric linkage. Neuraminidase activity could not be detected on the surface of M. gallisepticum, suggesting that this enzyme is not involved in the mechanism of adherence of sialoglycoproteins. Binding of sialoglycoproteins was time dependent, however, and markedly diminished with increasing ionic strength, but was largely unaffected between pH 4 and 9.

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