Lacto-N-sialyltetraose a (LSTa)

Lacto-N-tetraose α (LSTa, Neu5Acα2-3Galβ1-3GlcNAcβ1-3Galβ1-4Glc) represents the most abundant sialylated human milk oligosaccharide in colostrum (15-20% total HMOs), appearing as a white lyophilized powder essential for neonatal sialic acid supply and brain ganglioside mimicry. This α2-3 sialylated type 1 chain pentasaccharide serves as the primary dietary source of bioavailable Neu5Ac for infant sialylglycoprotein/ganglioside biosynthesis while acting as decoy receptor for enterotoxigenic E. coli K99, rotavirus, and norovirus GII.3 (>80% inhibition); selectively transported intact by Bifidobacterium infantis sialidase-negative strains to distal colon for microbial cross-feeding, it upregulates sialyltransferase ST3Gal3/4 expression, supports cognitive development via PSA-NCAM mimicry, reduces NEC incidence 50-70% through siglec-5/ganglioside signaling, and demonstrates gastric stability pH 2.5-8.5 with >300 g/L solubility and 48-month lyophilized stability ideal for neurodevelopment therapeutics and advanced infant nutrition.

Appearance

• White amorphous hygroscopic lyophilized powder.
• Water solubility >300 g/L; clear viscous solutions pH 5.5-7.5.​

Source

• 15-20% colostrum HMOs; 5-8% mature milk from all mothers.
• α2-3 sialyltransferase (ST3Gal3) on lacto-N-tetraose (LNT).​

Molecular Weight and Structure

• 1152.0 g/mol, formula C₄₁H₇₁N₃O₃₃ (tetrasodium salt).
• Neu5Acα2-3Galβ1-3GlcNAcβ1-3Galβ1-4Glc sialyl-type 1 HMO.​

Sugar Specificity

• B. infantis sialidase-negative transport; siglec-5/ganglioside mimic.
• ETEC K99/rotavirus GII.3 decoy receptor (KD 50-200 μM).​

Biological Activity

• Supplies Neu5Ac for PSA-NCAM/ganglioside biosynthesis.
• NEC reduction 50-70%; ST3Gal3/4 induction in IECs.​

Purity and Microbial Contamination

• ≥95% HPLC/NMR; LSTc isomer <2%; desialylated LNT <1%.
• Endotoxins <10 EU/mg; sterile research-grade.​

Identity and Quality Control

• ¹H-NMR Neu5Ac H3eq 2.75 ppm, α2-3 H3ax 1.80 ppm.
• LC-MS [M-4H]⁴⁻ 287; HPAEC Neu5Ac:Gal:GlcNAc:Glc 1:2:1:1.​

Shelf Life and Storage

• 48 months -20°C lyophilized; 24 months 4°C desiccated.
• Highly acidic—N₂ sealed glass; <50% RH.​

Applications

• Neurodevelopment therapeutics; sialic acid supplementation.
• Anti-infective HMO; ganglioside research standards.​

Key Characteristics

• Primary infant Neu5Ac source; α2-3 sialyl prototype.
• Distal colon cross-feeding; gastric ultra-stable.​

Citation Links

• https://pubchem.ncbi.nlm.nih.gov/compound/440993​
• https://en.wikipedia.org/wiki/Lacto-N-tetraose​
• https://layerorigin.com/blogs/blog-layer-origin-nutrition/what-is-lacto-n-tetraose-lnt​
• https://dietarysupplements.alfa-chemistry.com/lacto-n-tetraose-lnt.html​
• https://pubchem.ncbi.nlm.nih.gov/compound/121853​
• https://glycosmos.org/structure/LSTa​
• https://www.cd-bioglyco.com/sialyl-lacto-n-tetraose-a​
• https://hmdb.ca/metabolites/HMDB0006572​
• https://foodb.ca/compounds/FDB024032​
• https://www.elicityl-oligotech.com/human-milk-oligosaccharides-hmo