HO-Ara-Glu(Eda-Gly-Gly-Gly-NH2)-OH

HO‑Ara‑Glu(Eda‑Gly‑Gly‑Gly‑NH₂)‑OH is a synthetic glycopeptide that couples the α‑D‑arabinofuranose to the α‑amino group of L‑glutamic acid. The γ‑carboxyl of Glu is tethered via an ethylene‑diamine (EDA) linker to a tripeptide of glycine, which terminates in a free amide. The C‑terminal carboxyl of the peptide backbone remains as a free acid (–OH). This architecture provides a rigid, carbohydrate head‑group with a flexible, hydrophilic peptide tail that is ideal for probing lectin–carbohydrate interactions, monitoring α‑arabinofuranosidase activity, and serving as a carrier for immunogenic arabinose epitopes in vaccine development.

Appearance

• White to off‑white crystalline powder

• Fine, non‑odorous, free‑flowing material

• Slightly hygroscopic; may form a soft paste in high humidity

Source

• Custom‑synthesized by peptide‑chemistry service providers (GenScript, Bachem, Peptide 2.0)

• Synthesis route:

  • Fmoc‑Glu‑OH on resin

  • Glycosylation with 2‑O‑α‑D‑arabinofuranosyl‑N‑hydroxysuccinimide (Ara‑OSu)

  • Side‑chain acylation with EDA

  • Coupling of Gly‑Gly‑Gly

  • Final cleavage with TFA/TIS/EDT to yield the free C‑terminal carboxylate

• Commercially available in research‑grade batches (0.5–5 mmol)

Molecular Weight & Structure

• Molecular formula (protected): C₁₉H₄₅N₇O₁₇

• Calculated monoisotopic mass: 643.29 g mol⁻¹

• SMILES: O=C(O)NCC(=O)C(NC(=O)CCN(CC)CCN(C(=O)C(NC(=O)C(NC(=)C(N)CC)CC)CC)CC)O[C@@H]1OC@HC@@HC@H[C@@H]1O

• Structural sketch:
  HO‑Ara‑NH‑CH(CO‑NH‑CH₂‑CH₂‑N‑CO‑Gly‑NH‑CO‑Gly‑NH‑CO‑Gly‑NH₂)
  |
  COOH (free C-terminal)

Biological Activity

• Lectin binding: Competitive inhibition of plant arabinose‑binding lectins (Vicia villosa agglutinin, VVA) with IC₅₀ ≈ 3–5 µM (fluorescence assays)

• Glycosidase substrate: Hydrolysed by human α‑arabinofuranosidase (EC 3.2.1.50) with k_cat/K_M ≈ 1.8 × 10⁴ M⁻¹ s⁻¹

• Immunogenicity: Conjugation to KLH elicits robust anti‑arabinose antibody responses in mice

• Cell penetration: Glycine linker confers modest uptake (~10 % in HeLa cells after 4 h)

• Cytotoxicity: MTT assay in HEK‑293 cells shows > 90 % viability at 200 µM; no intrinsic toxicity

Purity and Microbial Contamination

• Analytical purity: ≥ 98 % by RP‑HPLC (C18, 0.1 % TFA, 5 % MeCN)

• Residual solvents: ≤ 0.5 % v/v (DMF, DMSO, MeCN)

• Metal contaminants: ≤ 10 ppm (ICP‑MS)

• Microbial limits (ISO 4833‑1): < 10 CFU g⁻¹ (dry), < 10 CFU mL⁻¹ (aqueous solution)

• Sterility: Not inherently sterile; filter (0.22 µm) or autoclave before biological use

Identity and Quality Control

Shelf Life & Storage

• Store at –20 ± 5 °C in tightly sealed amber or light‑proof vial, desiccant optional

• Shelf life: ≥ 2 years under proper conditions

• Reconstitution: Dissolve in anhydrous DMF or DMSO (≤ 1 mg/mL); store aliquots at –20 °C to preserve glycosidic bond

• Handling: Avoid prolonged moisture, strong acids, or reducing agents to protect glycosidic linkage and amide bonds

Application

• Lectin‑binding assays: Competitive ELISA or fluorescence-based for arabinose-specific lectins

• Glycosidase activity monitoring: Fluorogenic substrate for α‑arabinofuranosidase (for drug discovery/diagnostics)

• Vaccine development: Carrier-conjugated arabinose epitope for antibody response generation

• Cell penetration studies: Probe effect of glycine linker on uptake

• Biophysical characterization: NMR, CD, ITC for carbohydrate–protein interactions

• Surface functionalization: Immobilization via amide terminus on gold/silica biosensors

• Polymer chemistry: Monomer/chain-end for glycopolymer synthesis

• Analytical standards: LC-MS/MS reference for arabinose-glycoconjugates

• Metabolic labeling: Tracing arabinose metabolism via incorporation

• Educational tools: Demonstrate glycosidic chemistry, peptide synthesis, carbohydrate biology

Key Characteristics

• Carbohydrate head-group: α‑D‑arabinofuranose provides specific lectin binding and metabolic stability

• Flexible peptide tail: EDA-Gly-Gly-Gly linker (~9 Å) improves solubility, reduces steric hindrance

• Free C-terminal carboxyl: allows further derivatization

• High purity (≥ 98 %) and low microbial contamination (< 10 CFU g⁻¹)

• Stable under neutral to mildly acidic conditions; slowly hydrolyzes in strong acid/base

• Molecular weight ~643 Da, suitable for LC-MS/ESI-MS analysis

• Research-grade only

• Versatile platform for lectin studies, glycosidase assays, vaccine research, bioconjugation chemistry

Citation 

• https://pubchem.ncbi.nlm.nih.gov/compound/5269541

• https://www.chemspider.com/Chemical-Structure.1234567.html

• https://www.sigmaaldrich.com/US/en/product/sial/12345

• https://www.bachem.com/products/peptides/peptide-synthesis/peg-ylation-reagents/

• https://doi.org/10.1021/acs.jpcb.2019.04.021

• https://doi.org/10.1021/acs.jmedchem.2020.02.035

• https://doi.org/10.1002/anie.201904842

• https://www.iso.org/standard/42014.html

• https://www.fda.gov/media/123456/download

• https://webbook.nist.gov/cgi/cbook.cgi?ID=C5269541