1-(tert-butyl) 5-(2,5-dioxopyrolidin-1-yl) (16-(tert-butoxy)-16-oxohexadecanoyl)-L-glutamate [L-tBuO-Pal-Glu(OSu)-OtBu]

1-(tert-butyl) 5-(2,5-dioxopyrrolidin-1-yl) (16-(tert-butoxy)-16-oxohexadecanoyl)-L-glutamate, abbreviated as L-tBuO-Pal-Glu(OSu)-OtBu, is a synthetically derived building block used mainly for lipidating peptides, proteins, or other biomolecules. It features tert-butyl protected palmitic acid (tBuO-Pal), L-glutamic acid with a tert-butyl ester on the alpha carboxyl group, and an N-hydroxysuccinimide (NHS) ester (OSu) on the gamma carboxyl group. These dual tert-butyl esters allow orthogonal deprotection strategies. The long lipophilic palmitic acid chain enables membrane insertion, and the reactive NHS ester facilitates conjugation to primary amines. Applications include membrane-anchored peptide synthesis, liposomal formulations, protein modification, and hydrophobic surface coatings, with selective acidic deprotection allowing further tailored modifications.

Appearance

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

Source

• Chemically synthesized and not found naturally.

• Available from specialized chemical and bioconjugation reagent suppliers.

Molecular Weight and Structure

• Molecular Weight: Approximately 678.9 g/mol (C37H66N2O9).

• Structure: Palmitic acid (with tert-butyl ester), glutamic acid core with tert-butyl ester at alpha carboxyl; gamma carboxyl activated as NHS ester.

Biological Activity

• Biologically inert by itself; activity depends on conjugated biomolecules.

• Palmitate chain confers lipophilicity and membrane insertion.

• NHS ester allows conjugation to primary amines for bioconjugation.

Purity and Microbial Contamination

• Purity: Typically ≥ 95% by HPLC.

• Microbial contamination minimal or absent.

• Tested by LAL assay and sterility tests.

Identity and Quality Control

• Identity confirmed by MS, ¹H and ¹³C NMR, and IR spectroscopy.

• Purity determined by HPLC.

• NHS ester reactivity confirmed by amine quantification assay.

Shelf Life and Storage

Application

• Lipopeptide synthesis with membrane-anchoring features.

• Protein lipidation for enhanced membrane targeting.

• Liposomal drug formulation.

• Surface modification with hydrophobic lipid coatings.

• Bioconjugation reagent for covalent coupling to primary amines.

Key Characteristics

• Highly lipophilic palmitic acid chain with tert-butyl protection.

• Reactive NHS ester for bioconjugation.

• Orthogonal tert-butyl esters allow selective deprotection.

• Wide solubility in organic solvents like chloroform, DCM, and DMSO.

• Versatile in chemical synthesis approaches.

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 tert-butyl protected 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/