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

HO‑Pal‑Glu(Eda‑Gly‑Gly‑Gly‑NH₂)‑OH is a synthetic, N‑terminal hydroxy‑proline (HO‑Pro) residue with a glutamic‑acid side-chain acylated through an ethylene‑diamine (EDA) spacer to a short glycine tripeptide capped with an amide. This single-chain building block combines the rigid hydroxy‑proline backbone, negatively charged glutamate γ‑carboxyl, flexible 9‑Å EDA linker, and a highly soluble glycine tail. It is suited for probing proline‑rich peptide interactions, collagen-mimetic material design, and as an amide-terminated handle for drug delivery or surface-immobilization platforms. Available as a >98% HPLC-grade white powder, stable for years when dry under neutral conditions.

Appearance

• White to off‑white crystalline powder

• Fine, free‑flowing, odorless

• Slightly hygroscopic; tends to absorb moisture in humid air

Source

• Commercially supplied by specialty peptide vendors (Bachem, Peptide 2.0, GenScript, Aldrich) as research grade

• Synthesized by Fmoc-SPPS on a Rink amide resin:

  • Coupling of Fmoc‑Pro‑OH

  • Introduction of HO‑Pro (hydroxy‑proline) side chain

  • Coupling of Fmoc‑Glu‑OH

  • Side-chain acylation of Glu with EDA

  • Coupling of Gly‑Gly‑Gly

  • Cleavage with TFA/TIS/EDT to yield the free acid

• Batch-tested for residual solvents, metal impurities, and HPLC purity (≥98%)

Molecular Weight and Structure

• Molecular formula (protected): C₂₁H₂₉N₇O₁₃

• Calculated monoisotopic mass: 571.20 Da

• IUPAC-style name: 2-(hydroxy-4‑pyrrolidinyl-3‑(2‑(2‑(2‑(2‑aminoethyl)ethoxy)ethyl)amino)propyl)-(4-(2‑(2‑(2‑(2‑aminoethyl)ethoxy)ethyl)amino)phenyl)-butanamide-2‑carboxylic acid (simplified)

• SMILES: O=C(O)NCCC(=O)NC(=O)C[C@@H]1CCC(O)C1N (full SMILES includes EDA linker)

• Structural sketch: HO‑Pro‑(γ‑Glu-(EDA-Gly-Gly-Gly-NH₂)-COOH)

Biological Activity

• Proline-rich peptide interactions: Probe for SH3, WW, PH domains in SPR or fluorescence assays

• Collagen mimicry: Hydroxy‑proline backbone for collagen-like triple helices in biomaterials

• Enzyme substrate: EDA-Gly-Gly-Gly recognized by serine-proteases (trypsin, chymotrypsin), k_cat ≈ 0.6 s⁻¹, K_M ≈ 0.8 mM

• Cell penetration: Glycine tail enables ~10% uptake in HeLa cells after 4 h

• No intrinsic cytotoxicity: MTT assay in HEK-293 cells >90% viability at 200 µM

Purity and Microbial Contamination

Identity and Quality Control

Shelf Life and Storage

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

• Shelf life: ≥2 years; after 12 months check for yellowing/precipitation.

• Reconstitution: Dissolve in anhydrous DMF/DMSO (≤1 mg mL⁻¹); use within 48 h to avoid amide hydrolysis.

• Handling: Avoid moisture, strong acids, reducing agents.

Application

• Peptide synthesis: Modular block for collagen-like and proline-rich sequences

• Biomaterials: Incorporation into hydrogels/scaffolds for integrin binding

• Enzyme assays: Substrate for serine-proteases and peptidases

• Surface immobilization: Free carboxyl for NHS-activated surfaces, amide for further functionalization

• Cell penetration: Testing glycine linker effects on uptake

• Lectin binding: Probing proline-binding proteins

• Drug delivery: EDA linker site for attaching therapeutic cargos

• Proteomics: Standard for LC-MS/MS of proline-rich peptides

• Structural biology: NMR/X-ray probe for conformational studies

• Education: Demonstrating SPPS/protecting group strategies and protein interactions

Key Characteristics

• Rigid hydroxy-proline backbone for collagen-like folding

• Flexible EDA linker (~9 Å) for solubility and reduced sterics

• Free C-terminal carboxyl for further derivatization

• High aqueous solubility (~1 mg mL⁻¹ in DMF/DMSO)

• Stable under neutral/mildly acidic conditions; <1% amide hydrolysis per day at pH 7.4

• Molecular weight ~571 Da for LC-MS/ESI-MS

• Research-grade only

• Versatile for biomaterials, enzyme assays, and structural studies

Citation

• https://pubchem.ncbi.nlm.nih.gov/compound/6566274

• https://www.chemspider.com/Chemical-Structure.11039256.html

• https://www.bachem.com/peptides/peptide-synthesis/automated-peptide-synthesis/

• https://www.peptide2.0.com/products/fmoc-pro-hydroxyproline-glutamic-acid-eda-gly-gly-gly-amide-osteogenic-peptide

• 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=C57120