Fmoc-N-amido-dPEG®₃₆-TFP ester

Fmoc-N-amido-dPEG®36-TFP ester, product number 11008, is a protected amino-dPEG®-acid functionalized as the 2,3,5,6-tetrafluorophenyl (TFP) ester for efficient conjugation to an amine. A Fluorenylmethyloxycarbonyl (Fmoc) group protects the N-terminus of the product. Fmoc-N-amido-dPEG®36-TFP ester is designed for conjugation of a long, amphiphilic dPEG® spacer into a peptide chain. However, it will work in many other applications.

PEGylation with dPEG® Products
PEGylation is the covalent addition of polyethylene glycol (PEG) to a compound or surface. PEGylated compounds include proteins, peptides, dyes or other labels, and small molecule drugs.

Because PEG is amphiphilic, peptide synthesis often employs PEGylation to enhance the water solubility of hydrophobic peptides. Moreover, peptide PEGylation confers the following benefits on the resulting conjugates:

prolongs the in vivo circulation of conjugates by increasing the conjugate's hydrodynamic volume;
protects the peptide from proteolysis; and,
reduces or eliminates the antigenicity of the conjugated peptide.

However, conventional PEGs are dispersed polymers (Đ > 1.00). A typical dispersed polymer PEG consists of multiple chain lengths with various molecular weights. The stated molecular weight for a conventional PEG is an average of the distribution of chain lengths and molecular weights.

Oursingle molecular weight PEG products (known as "discrete PEG" and sold under the dPEG® trademark) provide all of the benefits of traditional, dispersed PEG without the analytical headache that comes from having an intractable mixture of conjugates, each with different PEG chain lengths.

Fmoc-N-amido-dPEG®36-TFP ester permits our customers to insert a long (111 atoms, 132.7 Å) dPEG® into a peptide chain using well-known, facile chemistry. The product works in solid-phase and solution-phase synthetic processes; however, it may work somewhat better in solution-phase chemistry.1

The dPEG® chain can be inserted at either end of a peptide or in the middle of two peptides as a highly flexible spacer. Furthermore, the dPEG® chain can provide extra distance in a synthetic construct where steric hindrance is a problem. The amphiphilic nature of dPEG® means that the construct will gain water solubility while retaining solubility in organic solvents. The Fmoc protecting group removes easily with a solution of piperidine in N, N-dimethylformamide (DMF).

Why Use TFP Esters?
TFP esters are generally superior to the more commonly used N-hydroxysuccinimidyl (NHS) esters. The 2,3,5,6-tetrafluorophenyl group is more stable to hydrolysis and more reactive to amines than NHS esters.

Fmoc-N-amido-dPEG®36-TFP ester, product number 11008, is part of a full line of Fmoc-protected amino-dPEG® active ester products. To help our customers discover the optimum dPEG® product for a particular project or application, we offer Fmoc-protected amino-dPEG® acids activated with either TFP or NHS. We also provide Fmoc-protected amino-dPEG® acids without active ester functionalization.

Application Reference:

Mäde, V.; Els-Heindl, S.; Beck-Sickinger, A. G. Automated Solid-Phase Peptide Synthesis to Obtain Therapeutic Peptides. Beilstein Journal of Organic Chemistry 2014, 10(1), 1197–1212. https://doi.org/10.3762/bjoc.10.118.

In the paper cited above, the authors were reporting on dispersed, not discrete, PEG; however, the caution may still apply to our single molecular weight dPEG® products.

Please contact us at for specific academic pricing.