α-Gal Lewis A (Galα1-3GlcNAcβ1-3(Fucα1-4)GlcNAc) 

• Pristine white to off-white amorphous or crystalline powder.
• Melting point ~200-210°C; water solubility >100 g/L.

Source

• Naturally in human A blood group secretions, gastrointestinal mucins, and select pathogens.
• Commercially via glycosyltransferase cascades on GlcNAc acceptors using E. coli or yeast expression systems.

Molecular Weight and Structure

• Molecular mass 811.73 g/mol, formula C₃₂H₅₅N₃O₂₄.
• Galα1-3GlcNAcβ1-3(Fucα1-4)GlcNAc branched scaffold with rigid glycosidic linkages.

Sugar Specificity

• Binds anti-α-Gal antibodies, Lewis lectins (e.g., LEA), and helminth adhesins via terminal Galα1-3 and Fucα1-4.
• Hydrolyzed by α-galactosidases (e.g., from Bacteroides) and α1-4 fucosidases.

Biological Activity

• Elicits IgE/IgG responses in α-Gal syndrome; inhibits norovirus/rotavirus adhesion.
• Modulates allergy, promotes T-reg cells, targets cancer glycans, and barriers xenotransplants.

Purity and Microbial Contamination

• ≥95-99% by HPLC/NMR; endotoxins <10 EU/mg, no pathogens.
• Heavy metals per ICH Q3D; moisture <10% post-lyophilization.

Identity and Quality Control

• ¹H-NMR for anomeric protons; LC-MS/MS for [M+H]+; HPAEC-PAD for monosaccharides.
• COA includes heavy metals (ICP-MS), residuals (GC-MS).

Shelf Life and Storage

• 24-36 months at -20°C under N₂, lyophilized.
• Ambient short-term if desiccated; avoid humidity to prevent hydrolysis.

Applications

• Blood typing assays, glycan arrays, anti-Gal vaccine development.
• Xenotransplant research, anti-infective mimics, functional foods.

Key Characteristics

• Gastric-stable; colonic fermentation to SCFAs; epitope mimicry for precise screening.

Citation Links

• https://en.wikipedia.org/wiki/Lewis_A_antigen
• https://pmc.ncbi.nlm.nih.gov/articles/PMC6344609/
• https://www.qa-bio.com/product/alpha1-3-gal-standard/
• https://pmc.ncbi.nlm.nih.gov/articles/PMC2271034/
• https://pubs.acs.org/doi/10.1021/ja0493205
• https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2020.01420/full
• https://glycosmos.org/
• https://pubmed.ncbi.nlm.nih.gov/40591906/
• https://academic.oup.com/glycob/article/12/4/241/1592386/cwe123.pdf
• https://www.sigmaaldrich.com/US/en/search/alpha-gal-lewis-a