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Fmoc-N-amido-dPEG®₄-acid (QBD-10213)



Fmoc-N-amido-dPEG®4-acid, product number QBD-10213, is one of a broad line of products designed for use in peptide synthesis. The short (16 atoms), discrete PEG (dPEG®) spacer is functionalized with a propionic acid group on one end and an Fmoc-protected amine on the other. The compound can be added to the N-terminus of a growing peptide chain or to a primary-amine-functionalized side chain of an amino acid such as lysine. The dPEG®4 spacer imparts water solubility to the peptide to which it is conjugated.

QBD-10213 permits our customers to insert a short (16 atoms) dPEG® into a peptide chain using familiar Fmoc chemistry. The product works equally well in solid phase and solution phase synthetic processes. The dPEG® can be inserted at either end of the peptide chain or in the middle of two amino acid sequences to provide a flexible spacer between distinct functional peptides. Additionally, the short dPEG® spacer can be used to provide extra distance in a synthetic construct where steric hindrance is a problem. The amphiphilic nature of dPEG® means that the construct will gain some degree of water solubility while remaining soluble in organic solvent. The Fmoc protecting group removes easily with a solution of piperidine in N,N-dimethylformamide (DMF).


Unit Size100 mg, 1000 mg
Molecular Weight487.54; single compound
Chemical formulaC₂₆H₃₃NO₈
Purity> 98%
SpacersdPEG® Spacer is 16 atoms and 18.0Å
Typical solubility properties (for additional information contact Customer Support)Methylene chloride, Acetontrile, DMAC or DMSO.
Storage and handling-20°C; Always let come to room temperature before opening; be careful to limit exposure to moisture and restore under an inert atmosphere; stock solutions can be prepared with dry solvent and kept for several days (freeze when not in use). dPEG® pegylation compounds are generally hygroscopic and should be treated as such. This will be less noticeable with liquids, but the solids will become tacky and difficult to manipulate, if care is not taken to minimize air exposure.


Greg T. Hermanson, Bioconjugate Techniques, 3rd Edition, Elsevier, Waltham, MA 02451, 2013, ISBN 978-0-12-382239-0; See Chapter 18, Discrete PEG Reagents, pp. 787-821, for a full overview of the dPEG® products.

Novel Synthetic Route to Peptide-Capped Gold Nanoparticles. Takeshi Serizawa, Yu Hirai, and Mamoru Aizawa. Langmuir. 2009, 25 (20), pp 12229–12234. September 21, 2009. DOI: 10.1021/la9021799.

Controlling HBV Replication in Vivo by Intravenous Administration of Triggered PEGylated siRNA-Nanoparticles. Sergio Carmona, Michael R. Jorgensen, Soumia Kolli, Carol Crowther, Felix H. Salazar, Patricia L. Marion, Masato Fujino, Yukikazu Natori, Maya Thanou, Patrick Arbuthnot, and Andrew D. Miller. Mol. Pharmaceutic., 2009, 6 (3), pp 706–717. January 21,2009. DOI: 10.1021/mp800157x.

Species Differences of Bombesin Analog Interactions with GRP-R Define the Choice of Animal Models in the Development of GRP-R-Targeting Drugs. Theodosia Maina, PhD; Berthold A. Nock, PhD; Hanwen Zhang, Anastasia Nikolopoulou, Msci, Beatrice Waser, PhD; Jean Claude Reubi, MD; and Helmut R. Maecke, PhD. Journal of Nuclear Medicine. 2005, 46 (5) pp. 823-830. January 23, 2005.

Polyproline-Rod Approach to Isolating Protein Targets of Bioactive Small Molecules: Isolation of a New Target of Indomethacin. Shin-ichi Sato, Youngjoo Kwon, Shinji Kamisuki, Neeta Srivastava, Quian Mao, Yoshinori Kawazoe, and Motonari Uesugi. J. Am. Chem. Soc. 2007, 129 (4), pp 873–880. January 4, 2007. DOI: 10.1021/ja0655643.

Photocleavable Peptide-Conjugated Magnetic Beads for Protein Kinase Assays by MALDI-TOF. MS. Guangchang Zhou, Xiaoliang Yan, Ding Wu, and Stephen J. Kron. Bioconjugate Chem. 2010, 21 (10), pp 1917–1924. September 22, 2010. DOI: 10.1021/bc1003058.

Neutrophil Targeting Heterobivalent SPECT Imaging Probe: cFLFLF-PEG-TKPPR-99mTc. Yi Zhang, Li Xiao, Mahendra D. Chordia, Landon W. Locke, Mark B. Williams, Stuart S. Berr, and Dongfeng Pan. Bioconjugate Chem. 2010, 21 (10), pp 1788–1793. September 15, 2010. DOI: 10.1021/bc100063a.

Evaluation of 99mTc-Labeled Cyclic RGD Peptide with a PEG4 Linker for Thrombosis Imaging: Comparison with DMP444. Wei Fang, Jia He, Young-Seung Kim, Yang Zhou, and Shuang Liu. Bioconjugate Chem. 2011, 22 (8), pp 1715–1722. July 24, 2011. DOI: 10.1021/bc2003742.

Expanding the Scope of Biocatalysis: Oxidative Biotransformations on Solid-Supported Substrates. Sarah J. Brooks, Lydie Coulombel, Disha Ahuja, Douglas S. Clark, and Jonathan S. Dordick. Advanced Synthesis & Catalysis. 2008, 350 (10), pp 1517–1525. July 7, 2008. DOI:10.1002/adsc.200800188.

Development of Peptide Nucleic Acid Probes for Detection of the HER2 Oncogene.
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Enhanced Cellular Uptake of Peptide-Targeted Nanoparticles through Increased Peptide Hydrophilicity and Optimized Ethylene Glycol Peptide-Linker Length. Jared F. Stefanick, Jonathan D. Ashley, and Basar Bilgicer. ACS Nano. 2013, 7 (9) pp 8115–8127. August 29, 2013. DOI: 10.1021/nn4033954.

PulmoBind, an Adrenomedullin-Based Molecular Lung Imaging Tool. Myriam Létourneau, Quang Trinh Nguyen, Francois Harel, Alain Fournier, and Jocelyn Dupuis. J Nucl Med. 2013, 54 (10) pp 1789-1796. October 1, 2013. DOI:10.2967/jnumed.112.118984.

Liposomes containing monophosphoryl lipid A: A potent adjuvant system for inducing antibodies to heroin hapten analogs. Gary R. Matyas, Alexander V. Mayorova, Kenner C. Rice, Arthur E. Jacobson, Kejun Cheng, Malliga R. Iyer, Fuying Li, Zoltan Becka, Kim D. Janda, Carl R. Alvinga. Vaccine. 2013, 31 (26) pp 2804-2810. June 10, 2013.

Design of a heterotetravalent synthetic allergen that reflects epitope heterogeneity and IgE antibody variability to study mast cell degranulation. Michael W. Handlogten, Tanyel Kiziltepe and Basar Bilgicer. Biochem. J. 2013, 449 pp 91–99. October 11, 2011. DOI:10.1042/BJ20121088.

Design of a Heterobivalent Ligand to Inhibit IgE Clustering on Mast Cells. Michael W. Handlogten, Tanyel Kiziltepe, Demetri T. Moustakas, and Basxar Bilgicer. Chemistry & Biology. 2011, 18 (9) pp 1179–1188. September 23, 2011. DOI 10.1016/j.chembiol.2011.06.012.

Robust Sensing Films for Pathogen Detection and Medical Diagnostics. Aaron S. Anderson ; Andrew M. Dattelbaum ; Harshini Mukundan ;Dominique N. Price ; W. Kevin Grace ; Basil I. Swanson. Frontiers in Pathogen Detection: From Nanosensors to Systems., 2009, Proc. Of SPIE 7167. 71670q-1 February 18, 2009. 10.1117/12.809383.

Optical Imaging of Integrin αv β3 Expression with Near-Infrared Fluorescent RGD Dimer with Tetra(ethylene glycol) Linkers. Zhaofei Liu, Shuanglong Liu, Gang Niu, Fan Wang, Shuang Liu, Xiaoyuan Chen. Mol Imaging. 2010, 9 (1) pp 21-29. February 1, 2010. DOI:

Spring-Loaded Model Revisited: Paramyxovirus Fusion Requires Engagement of a Receptor Binding Protein beyond Initial Triggering of the Fusion Protein. Matteo Porotto, Ilaria DeVito, Samantha G. Palmer, Eric M. Jurgens, Jia L. Yee, Christine C. Yokoyama, Antonello Pessi and Anne Moscona. J. Virol. 2011, 85 (24) pp 12867-12880. DOI: 10.1128/JVI.05873-11.

Tumor Uptake of the RGD Dimeric Probe 99mTc-G3-2P4-RGD2 is Correlated with Integrin rv_3 Expressed on both Tumor Cells and Neovasculature. Zhaofei Liu, Bing Jia, Jiyun Shi, Xiaona Jin, Huiyun Zhao, Fang Li, Shuang Liu, and Fan Wang. Bioconjugate Chem. 2010, 21 (3) pp 548-555. February 25, 2010. DOI: 10.1021/bc900547d.

Quantifying Cellular Internalization with a Fluorescent Click Sensor. Laura I. Selby, Luigi Aurelio, Daniel Yuen, Bim Graham, and Angus P. R. Johnston. ACS Sensors. 2018, 3, pp 1182-1189. April 20, 2018. DOI: 10.1021/acssensors.8b00219.

Radionuclides in Targeted Therapy of Cancer. Adina Elena STANCIU. Rev. Roum. Chim. 2012, 57 (1) pp 5-13. May 27, 2011. DOI:

Improving Tumor-Targeting Capability and Pharmacokinetics of 99mTc-Labeled Cyclic RGD Dimers with PEG4 Linkers. Lijun Wang, Jiyun Shi, Young-Seung Kim, Shizhen Zhai, Bing Jia, Huiyun Zhao, Zhaofei Liu, Fan Wang, Xiaoyuan Chen and Shuang Liu. Molecular Pharmaceutics. 2009, 6 (1) pp 231–245. December 9, 2008. DOI: 10.1021/mp800150r.

Improving Tumor Uptake and Pharmacokinetics of 64Cu-Labeled Cyclic RGD Peptide Dimers with Gly3 and PEG4 Linkers. Jiyun Shi, Young-Seung Kim, Shizhen Zhai, Zhaofei Liu, Xiaoyuan Chen and Shuang Liu. Bioconjugate Chemistry. 2009, 20 (4) pp 750–759. March 25, 2009. DOI: 10.1021/bc800455p.

Evaluation of the Pharmacokinetic Effects of Various Linking Group Using the 111In-DOTA-X-BBN(7−14)NH2 Structural Paradigm in a Prostate Cancer Model. Jered C. Garrison, Tammy L. Rold, Gary L. Sieckman, Farah Naz, Samantha V. Sublett, Said Daibes Figueroa, Wynn A. Volkert and Timothy J. Hoffman. Bioconjugate Chem. 2008, 19 (9) pp 1803–1812. August 20, 2008. DOI: 10.1021/bc8001375.

Two 90Y-Labeled Multimeric RGD Peptides RGD4 and 3PRGD2 for Integrin Targeted Radionuclide Therapy. Zhaofei Liu, Jiyun Shi, Bing Jia, Zilin Yu, Yan Liu, Huiyun Zhao, Fang Li, Jie Tian, Xiaoyuan Chen, Shuang Liu, and Fan Wang.Two 90Y-Labeled Multimeric RGD Peptides RGD4 and 3PRGD2 for Integrin Targeted Radionuclide Therapy. Zhaofei Liu, Jiyun Shi, Bing Jia, Zilin Yu, Yan Liu, Huiyun Zhao, Fang Li, Jie Tian, Xiaoyuan Chen, Shuang Liu, and Fan Wang. Mol. Pharmaceutics. 2011, 8 (2) pp 591–599. January 19, 2011. DOI: 10.1021/mp100403y.

Impact of PKM Linkers on Biodistribution Characteristics of the 99mTc-Labeled Cyclic RGDfK Dimer. Shuang Liu, Zhengjie He, Wen-Yuan Hsieh, Young-Seung Kim, and Young Jiang. Bioconjugate Chem. 2006, 17 (6) pp 1499–1507. November 1, 2006. DOI: 10.1021/bc060235l.

99mTc-Galacto-RGD2: A Novel 99mTc-Labeled Cyclic RGD Peptide Dimer Useful for Tumor Imaging. Shundong Ji, Andrzej Czerwinski, Yang Zhou, Guoqiang Shao, Francisco Valenzuela, Paweł Sowiński, Satendra Chauhan, Michael Pennington, and Shuang Liu. Mol. Pharmaceutics. 2013, 10 (9) pp 3304–3314. July 22, 2013. DOI: 10.1021/mp400085d.

2-Mercaptoacetylglycylglycyl (MAG2) as a Bifunctional Chelator for 99mTc-Labeling of Cyclic RGD Dimers: Effect of Technetium Chelate on Tumor Uptake and Pharmacokinetics. Jiyun Shi, Young-Seung Kim, Sudipta Chakraborty, Bing Jia, Fan Wang and Shuang Liu. Bioconjugate Chemistry. 2009, 20(8) pp 1559–1568. July 15, 2009. DOI: 10.1021/bc9001739.

Robust Sensing Films for Pathogen Detection and Medical Diagnostics. Aaron S. Anderson ; Andrew M. Dattelbaum ; Harshini Mukundan ;Dominique N. Price ; W. Kevin Grace ; Basil I. Swanson. Frontiers in Pathogen Detection: From Nanosensors to Systems., 2009, Proc. Of SPIE 7167. 71670q-1 February 18, 2009. 10.1117/12.809383.

PEG-Peptide Conjugates. Ian W Hamley. Biomacromolecules. 2014. April 1, 2014. DOI: 10.1021/bm500246w.

Molecular Imaging of the Human Pulmonary Vascular Endothelium Using an Adrenomedullin Receptor Ligand. Francois Harel, Xavier Levac, Quang T. Nguyen, Myriam Le´tourneau, Sophie Marcil, Vincent Finnerty, Marie`ve Cossette, Alain Fournier, and Jocelyn Dupuis. Molecular Imaging. 2015, pp 1-9. March 1, 2015. DOI: 10.2310/7290.2015.00003.

Toward the Optimization of Bombesin-Based Radiotracers for Tumor Targeting. Ibai E. Valverde, Sandra Vomstein, and Thomas L. Mindt. Journal of Medicinal Chemistry. 2016, April 7, 2016. DOI: 10.1021/acs.jmedchem.6b00025.

In vitro and in vivo efficacy, toxicity, bio-distribution and resistance selection of a novel antibacterial drug candidate. Jlenia Brunetti, Chiara Falciani, Giulia Roscia, Simona Pollini, Stefano Bindi, Silvia Scali, Unai Cossio Arrieta, Vanessa Gomez-Vallejo, Leila Quercini, Elisa Lbba, Marco Prato, Gian Maria Rossolini, Jordi Llop, Luisa Bracci, and Alessandro Pini. Scientific Reports. 2016, 6 (26077). May 12, 2016. DOI: 10.1038/srep26077.

Activity-based protein profiling reveals active serine proteases that drive malignancy of human ovarian clear cell carcinoma. Christine Mehner, Alexandra Hockla, Mathew Coban, Benjamin Madden, Rosendo Estrada, Derek C Radisky, Evette S Radisky. Journal Of Biological Chemistry. 2022. Volume 298, Issue 8. June 16, 2022.

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