Sialic acid patterns in N‐linked carbohydrate chains. Structural analysis of the N‐acetyl‐/N‐glycolyl‐neuraminic‐acid‐containing N‐linked carbohydrate chains of bovine fibrinogen

Abstract

Abstract. The N-linked carbohydrate chains of bovine fibrinogen have been released by peptide--N4-(N-acetyl-P-glucosaminyl)asparagine amidase-F, fractionated by FPLC and HPLC procedures and characterized by 500/600-MHz 'H NMR spectroscopy. Evidence is presented for the native sialic acid patterns, involving the occurrence of a 2 + 6-linked N-acetyl-and N-glycolylneuraminic acid residues in the terminal position of the di-antennary carbohydrate chains. Details are included of minor oligosaccharides containing NeuSAcu2 --t 3GalP1-+ 4/Pl -+ 3GlcNAc pl + structural elements, which have not been previously described in this glycoprotein.

N- and O-Glycosylation of a Commercial Bovine Whey Protein Product

“…The partial presence of (α1–6)-linked core Fuc residues is reflected by the Fuc CH 3 signals at δ 1.208 (linkage to GlcNAc- 1α ) and 1.221 (linkage to GlcNAc- 1β ), combined with the GlcNAc- 1 H-1α, GlcNAc- 2 H-1, and GlcNAc- 2 NAc signals at δ 5.182, 4.666, and 2.096, respectively. In the case of nonfucosylation, these parameters are found at δ 5.188, ∼4.61, and 2.081. − In the 4.4–4.7 ppm region, several signals are observed corresponding with the H-1 atoms of GlcNAc- 2 and the antennary Gal, GlcNAc, and GalNAc residues. In the 4.9–5.5 ppm region, several signals are detected belonging to the αMan H-1 atoms of oligomannose segments, e.g., Man- A , when substituted by Man- D 2 , δ 5.411; terminal Man- A , δ 5.089; Man- 4 , when substituted by Man- C , δ 5.345/5.336; Man- C , when substituted by Man- D 1 , δ 5.310; terminal Man- D 2 /Man- C , δ 5.054; terminal Man- D 1 /Man- D 3 , δ 5.041; Man- B , when substituted by Man- D 3 , δ 5.143 (Man- 4 of complex-type system, δ 5.134).…”

N‐glycolylneuraminic acid in red meat and processed meat is a health concern: A review on the formation, health risk, and reduction

“…The N‐sugar chain contains a few to dozens of monosaccharides, including Sia, galactose (Gal), mannose (Man), fucose (Fuc), N ‐acetylglucosamine (GlcNAc), and N ‐acetylgalactosamine (GalNAc) (Bell et al., 2023). Sia bonds with Gal residues or GalNAc residues at the secondary end of the glycans via α‐2,3‐ or α‐2,6‐ linkages (Breg et al., 1987; Pfeiffer et al., 1992; Spik et al., 1988; Vliegenthart et al., 2010), or bonds with GlcNAc at the secondary end of the glycans via an α‐2,6‐ linkage (Mizuochi et al., 1979), or connects to other Sia residues via α‐2,8‐ or α‐2,9‐ linkages (Finne, 1985; Iwasaki et al., 1984). The linkage between Sia and sugar residues in the N‐sugar chain is depicted in Figure 2.…”

Exploration of the Sialic Acid World

“…Over the years, the two sialic acids have been found to be attached to D-galactose (Gal) via (α2!3) [419][420][421][422][423] or (α2!6) [423][424][425] linkages, to N-acetyl-D-galactosamine (GalNAc) via (α2!3) [426][427][428] or (α2!6) 421,429-432 linkages, and to N-acetyl-D-glucosamine (GlcNAc) via an (α2!6) linkage. 433 At the end of the 1970s, mid-1980s, terminal N-acylneuraminic acids were also discovered to be (α2!8)-linked [434][435][436] or (α2!9)-linked 437,438 with internal N-acylneuraminic acids, a phenomenon that was already seen in the 1960s for glycolipids (see Section 8.2).…”