GlcNAcβ1-3(Neu5Acα2-6)Galβ1-4GlcNAc (sialyl-lacto-N-triose II, branched trisaccharide HMO/neural glycan) appears as a white lyophilized powder essential for neurodevelopment research, influenza receptor mimicry, and Bifidobacterium prebiotic studies. This branched structure features GlcNAcβ1-3 linked to sialylated LacNAc [Neu5Acα2-6Galβ1-4GlcNAc], serving as the minimal receptor for human-adapted influenza viruses (H1N1, H3N2) via avian-to-human receptor switch, while selectively consumed by B. infantis for acetate production and pathogen blockade; prevalent in human milk oligosaccharides (1-3%), brain gangliosides, and tumor sialyl-glycans, it is chemoenzymatically synthesized (>97% purity via α2-6 sialyltransferase/β3GnT2 cascade) with gastric stability, siglec-2/3 binding for immune modulation, and key roles in NEC prevention, cognitive development via ganglioside mimicry, and anti-viral glycomimetics, exhibiting 48-month frozen stability.
Appearance
- White to off-white amorphous lyophilized powder, hygroscopic.
- Water solubility >150 g/L; clear colorless solutions pH 6-7.
Source
- 1-3% of human milk oligosaccharides; abundant in neural gangliosides.
- Enzymatic cascade: α2-6ST on LacNAc + β1-3GlcNAc-T on sialyl-LacNAc.
Molecular Weight and Structure
- 852.8 g/mol, formula C₃₂H₅₄N₄O₂₄ (sodium salt).
- Branched: GlcNAcβ1-3[Neu5Acα2-6Galβ1-4GlcNAc] core HMO/neuroglycan.
Sugar Specificity
- Human influenza HA binding (KD 2-5 mM); siglec-2/3, CD22 ligands.
- Hydrolyzed by Bifidobacterium sialidase + β3GlcNAc-ase.
Biological Activity
- Blocks avian→human flu receptor switch; prebiotic for B. infantis.
- Upregulates neural claudins; anti-NEC via barrier enhancement.
Purity and Microbial Contamination
- ≥97% HPLC/NMR; endotoxins <10 EU/mg LAL-validated.
- Sterile; heavy metals <0.5 ppm; moisture <6%.
Identity and Quality Control
- ¹H-NMR (Neu5Ac H3ax 1.8 ppm, Sia NAc 2.03 ppm); LC-MS [M-2H]²⁻ 425.
- HPAEC confirms GlcNAc:Gal:GlcNAc:Sia 2:1:1:1; linkage-specific.
Shelf Life and Storage
- 48 months -20°C lyophilized under N₂; 12 months 4°C desiccated.
- Avoid freeze-thaw cycles; store desiccated.
Applications
- Influenza receptor standards; siglec modulator screening.
- Neural development assays; anti-viral glycomimetics.
Key Characteristics
- Dual α2-6 Sia + type 1 chain specificity; gastric-stable.
- Minimal human flu receptor motif; B. infantis selective.
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