X-NeuNAc Methyl Ester

• White to pale yellow crystalline powder, non-hygroscopic.
• Soluble in DMSO/EtOH (>20 mM); moderately water-soluble (2-5 mM).

Source

• Chemical synthesis: per-O-acetyl-α-NeuNAc methyl ester glycosylated with protected 5-Br-4-Cl-indol-3-ol, followed by Zemplén deacetylation.
• Research grade from specialized glycochemistry suppliers.

Molecular Weight and Structure

• C20H24BrClN2O9, 551.77 g/mol; exact mass 551.9812 Da.
• Methyl 5-acetamido-2-(5-bromo-4-chloro-1H-indol-3-yloxy)-4-hydroxy-6-[(1R,2R)-1,2,3-trihydroxypropyl]oxane-2-carboxylate.

Sugar Specificity

• Selective for α-2,3/α-2,6-sialidases; Km 0.1-0.4 mM bacterial/viral enzymes.
• No hydrolysis by mammalian CMP-NeuAc synthetases or glycosyltransferases.

Biological Activity

• Sialidase cleavage → indolyl + MeO-Neu5Ac → dark blue insoluble pigment.
• Optimal pH 6.0-7.4, 37°C; visible in 15-60 min; stable permanent stain.

Purity and Microbial Contamination

• ≥98% HPLC purity; α-anomer >97%; free indoxyl <0.05%.
• Endotoxin-free; sterile; no contaminating neuraminidase activity.

Identity and Quality Control

• HRMS (m/z 552.1 [M+H]+), 1H-NMR (H-3eq/ax 2.7/2.9 ppm), functional staining assay.
• Chiral purity verified; CAS confirmed for research standards.

Shelf Life and Storage

• 36 months at -20°C desiccated; light-protected amber vials.
• DMSO stocks stable >12 months -80°C; avoid aqueous long-term storage.

Application

• Live-cell sialidase activity imaging; bacterial pathogenesis studies.
• Viral neuraminidase HTS inhibitor screening; glycan microarray validation.
• Histochemical detection in tissue sections, biofilm analysis.

Key Characteristics

• Lipid-soluble methyl ester enables membrane permeability; no salt required.
• Permanent dark blue precipitate; superior to soluble chromogens.