(S)-16-((1-(tert-butoxy)-5-((2,5-dioxopyrrolidin-1-yl)oxyl)-1,5-dioxopentan-2-yl)amino)-16-oxohexadecanoic acid [L-HO-Pal-Glu(OSu)-OtBu]

(S)-16-((1-(tert-butoxy)-5-((2,5-dioxopyrrolidin-1-yl)oxyl)-1,5-dioxopentan-2-yl)amino)-16-oxohexadecanoic acid, abbreviated as L-HO-Pal-Glu(OSu)-OtBu, is a synthetic building block used for lipidating peptides and proteins. This compound combines hydroxylated palmitic acid (HO-Pal), glutamic acid bearing a tert-butyl ester (OtBu) protecting its alpha carboxyl, and an N-hydroxysuccinimide (NHS) ester (OSu) activating the gamma carboxyl. The hydroxyl group on palmitic acid enables further modification. The palmitic acid confers lipophilicity for membrane insertion, and the NHS ester provides a reactive site for conjugation to primary amines. Applications include drug delivery membrane anchoring, liposomal formulations, and protein surface modifications. The tert-butyl ester allows selective acidic deprotection for controlled modification.

Appearance

• White to off-white solid, potentially waxy due to the palmitic acid chain.

Source

• Synthesized chemically; not naturally occurring.

• Available from specialized chemical suppliers.

Molecular Weight and Structure

• Molecular weight approximately 640.8 g/mol (C33H58N2O10).

• Structure features hydroxylated palmitic acid attached to glutamic acid with tert-butyl ester protection and NHS ester activation.

Biological Activity

• Biologically inert alone; biological role depends on conjugated molecule.

• Lipophilic chain facilitates membrane interaction; NHS ester allows covalent conjugation.

Purity and Microbial Contamination

• Purity generally ≥ 95% by HPLC.

• Minimal microbial contamination; verified by LAL and sterility testing.

Identity and Quality Control

• Verified by mass spectrometry, ¹H and ¹³C NMR, and IR spectroscopy.

• Purity measured by HPLC; NHS ester reactivity confirmed via amine quantification.

Shelf Life and Storage

Application

• Membrane-anchored lipopeptide synthesis.

• Protein lipid modification for membrane targeting.

• Liposomal drug delivery formulations.

• Surface hydrophobic modification.

• Bioconjugation reagent for selective amine coupling.

Key Characteristics

• High lipophilicity from hydroxylated palmitic acid.

• Reactive NHS ester for conjugation.

• Selective tert-butyl ester protection for acid-labile deprotection.

• Soluble in organic solvents like chloroform, DCM, DMSO.

• Versatile for chemical synthesis and modification.

Citation

• NHS ester lipid conjugation chemistry and bioconjugation applications:
  https://pubmed.ncbi.nlm.nih.gov/30613757/

• Palmitoylation and lipid modification of peptides and proteins:
  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6653962/

• Synthetic lipopeptides and amphiphiles in biomedical research:
  https://www.sciencedirect.com/science/article/pii/S0142961219304954

• Use of tert-butyl esters in synthetic organic and peptide chemistry:
  https://doi.org/10.1016/j.tet.2014.11.058

• NHS esters in protein modification and targeted drug delivery:
  https://pubmed.ncbi.nlm.nih.gov/20420327/

• Liposomal formulations incorporating NHS ester-functionalized lipids:
  https://pubmed.ncbi.nlm.nih.gov/30817167/

• Self-assembling peptides modified with lipid chains:
  https://pubmed.ncbi.nlm.nih.gov/29395641/

• Patents on lipid-NHS ester conjugates and therapeutic lipopeptides:
  https://patents.google.com/patent/US20170268536A1/en

• Chemical databases with structures of hydroxylated palmitoyl-glutamate derivatives:
  https://pubchem.ncbi.nlm.nih.gov/compound/5386443

• Reviews on fatty acylation and lipidation techniques in peptide therapeutics:
  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5357263/