Azido-dPEG®₄-acid

Azido-dPEG®4-acid, product number 10502, is a click chemistry crosslinking reagent. The azide moiety on one end of the molecule is useful for copper(I)-catalyzed click chemistry or copper-free click chemistry. Between the azide moiety and the propanoic acid moiety on the other end of the molecule is a single molecular weight, discrete polyethylene glycol (dPEG®) spacer. The propanoic acid moiety can be coupled to a primary or secondary amine by an acylation reaction. The azide also functions as a masked amine. In this application, the carboxylic acid end reacts first with an amine to form a peptide bond, followed by reduction of the azide to an amine for further reaction.

Click chemistry enables rapid, chemoselective, stereospecific reactions between an azide and an alkyne leading to the formation of a triazole ring joining the two reacted molecules. Since its publication in 2001, click chemistry has grown consistently in popularity and importance for the development of new chemical structures. Copper (I) catalyzed the first-reported click chemistry reactions. These reactions are known as Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC). Subsequently, copper-free click chemistry (formally known as strain promoted azide-alkyne cycloaddition, or SPAAC) was developed to facilitate click chemistry reactions in living cells without the use of toxic copper salts.

Activation of the propanoic acid moiety with an acylating agent enables conjugation of azido-dPEG®4-acid to a primary or secondary amine. Popular acylating agents include such as N-hydroxysuccinimide (NHS); 2,3,5,6-tetrafluorophenol (TFP); or 2,3,4,5,6-pentafluorophenol (PFP). Alternatively, 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) or another suitable carbodiimide can be used to couple the acid moiety directly to an amine without prior activation.

OurdPEG® products are single molecular weight products. Unlike traditional, polymeric polyethylene glycol (PEG), dPEG® products contain a single molecular weight PEG chain with a discrete chain length.

We offer various click chemistry reagents, including a broad array of azide-functionalized dPEG® products and dPEG® products functionalized with dibenzyl cyclooctyne (DBCO) for SPAAC.

If you need bulk product in a larger package size than our standard sizes, please contact us for a quote. Our commercial capabilities permit us to manufacture this product at any scale that you need.

Application References:

Hermanson, G. T. Chapter 17, Chemoselective Ligation; Bioorthogonal Reagents. Bioconjugate Techniques, 3rd edition. Academic Press: New York, 2013, pp 757-786, particularly pages 769-775 where click chemistry various.
Hermanson, G. T. Chapter 18, PEGylation and Synthetic Polymer Modification. Bioconjugate Techniques, 3rd edition. Academic Press: New York, 2013, pp 787-838.
Kolb, H. C.; Finn, M. G.; Sharpless, K. B. Click Chemistry: Diverse Chemical Function from a Few Good Reactions. Angew. Chem. Int. Ed., 2001, 40, 2004-2021.
Kolb, H. C.; Sharpless, K. B. The growing impact of click chemistry on drug discovery. Drug Disc. Today, 2003, 8(24), 1128-1137.
Baskin, J. M.; Bertozzi, C. R. Bioorthogonal Click Chemistry: Covalent Labeling in Living Systems. QSAR & Combinatorial Science 2007, 26(11–12), 1211–1219. https://doi.org/10.1002/qsar.200740086.
Patterson, D. M.; Nazarova, L. A.; Prescher, J. A. Finding the Right (Bioorthogonal) Chemistry. ACS Chem. Biol. 2014, 9(3), 592–605. https://doi.org/10.1021/cb400828a.
Dommerholt, J.; Rutjes, F. P. J. T.; van Delft, F. L. Strain-Promoted 1,3-Dipolar Cycloaddition of Cycloalkynes and Organic Azides. Top. Curr. Chem. (Z) 2016, 374(2), 16. https://doi.org/10.1007/s41061-016-0016-4

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