Free N-Acetylneuraminic Acid in Tissues in Salla Disease and the Enzymes Involved in Its Metabolism

AbstractN-Acetylneuraminic acid is the most abundant sialic acid (SA) in humans and is expressed as the terminal sugar on intestinal mucus glycans. Several pathogenic bacteria harvest and display host SA on their own surfaces to evade Siglec-mediated host immunity. While previous studies have identified bacterial enzymes associated with SA catabolism, no reported methods permit the selective labeling, tracking, and quantitation of SA-presenting microbes within complex multi-microbial systems. We combined metabolic labeling, click chemistry, 16S rRNA gene, and whole-genome sequencing to track and identify SA-presenting microbes from a cultured human fecal microbiome. We isolated a new strain of Escherichia coli that incorporates SA onto its own surface and encodes for the nanT, neuA, and neuS genes necessary for harvesting and presenting SA. Our method is applicable to the identification of SA-presenting bacteria from human, animal, and environmental microbiomes, as well as providing an entry point for the investigation of surface-expressed SA-associated structures.

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Thyroid-stimulating hormone binding to beef thyroid membranes. Role of N-acetylneuraminic acid.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(17)33288-x ◽

1976 ◽

Vol 251 (14) ◽

pp. 4247-4253 ◽

Cited By ~ 1

Author(s):

W V Moore ◽

L Feldman

Keyword(s):

Thyroid Stimulating Hormone ◽

Hormone Binding ◽

Acetylneuraminic Acid ◽

Stimulating Hormone

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Molecular characterization of cytidine monophospho-N-acetylneuraminic acid hydroxylase (CMAH) gene and frequency of blood types in stray cats of İzmir, Turkey

BMC Genomics ◽

10.1186/s12864-021-07588-0 ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Hüseyin Can ◽

Sedef Erkunt Alak ◽

Ahmet Efe Köseoğlu ◽

Umut Şahar ◽

Berna Bostanbaş ◽

...

Keyword(s):

Type A ◽

Type B ◽

Exon 2 ◽

Blood Types ◽

Acetylneuraminic Acid ◽

Stray Cats ◽

High Prevalence ◽

Heterozygous Form ◽

Type Ab ◽

First Time

Abstract Background Cytidine monophospho-n-acetylneuraminic acid hydroxylase (CMAH) gene associated with blood groups in cats encodes CMAH enzyme that converts Neu5Ac to Neu5Gc. Although variations in CMAH gene of pedigree cats have been revealed, the presence/lack of them in non-pedigree stray cats is unknown. Therefore, the present study aimed to investigate the variations in CMAH gene and the quantity of Neu5Ac and Neu5Gc on erythrocytes of non-pedigree stray cats (n:12) living in İzmir, Turkey. Also, the frequency of blood types was determined in 76 stray cats including 12 cats that were used for CMAH and Neu5A/Neu5Gc analysis. Results In total, 14 SNPs were detected in 5’UTR as well as in exon 2, 4, 9, 10, 11 and 12 of CMAH gene. Among these SNPs, -495 C > T in 5’UTR was detected for the first time as heterozygous in type A and AB cats, and homozygous and heterozygous in type B cats. The remaining 13 that have been detected in previous studies were also found as homozygous or heterozygous. Both Neu5Gc and Neu5Ac were detected in type A and AB cats. In type B cats, only Neu5Ac was detected. Among two type AB cats, the level of Neu5Ac was found higher in cat carrying heterozygous form (T/C) of 1392T > C. The prevalence of type B cats (67.1 %) was higher than others. Conclusions The presence of a new SNP as well as previous SNPs indicates that more variations can be found in stray cats with a more comprehensive study in the future. Also, the high prevalence of type B cats demonstrates the possible risk of neonatal isoerythrolysis among stray cats living in İzmir, Turkey.

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Characterization of glycopeptides derived from the low-density lipoprotein of hen's egg yolk

Canadian Journal of Biochemistry ◽

10.1139/o68-147 ◽

1968 ◽

Vol 46 (8) ◽

pp. 983-988 ◽

Cited By ~ 6

Author(s):

J. Z. Augustyniak ◽

W. G. Martin

Keyword(s):

Low Density Lipoprotein ◽

Density Lipoprotein ◽

Egg Yolk ◽

Low Density ◽

Amide Nitrogen ◽

Acetylneuraminic Acid ◽

Hen’S Egg ◽

Terminal Amino ◽

Protein Moiety

Two glycopeptides (A and B) were isolated from pronase-digested vitellenin, the protein moiety of the low-density lipoprotein of hen's egg yolk. Aspartic acid was the only N-terminal amino acid of both glycopeptides but only A contained N-acetylneuraminic acid. A contained 55% hexose (mannose), 14% hexosamine, 12% N-acetylneuraminic acid, 0.71% amide nitrogen, and its molecular weight was 2.3 × 103. The corresponding values for B were 64, 17, 0.0, 0.75, and 2.0 × 103. Chemical analyses showed that B (and probably A) occurs in vitellenin with the heteropolysaccharide group bound N-glycosidically via the β-amide group of an asparaginyl residue. The indicated structure is R∙(NH)Asp∙Thr∙Ser∙(Ala, Gly, Val)∙Ile, where R, the heteropolysaccharide group, contains 2 hexosamine and 8 hexose residues.

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

Biochemical Journal ◽

10.1042/bj2630355 ◽

1989 ◽

Vol 263 (2) ◽

pp. 355-363 ◽

Cited By ~ 51

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.

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