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Methoxytrityl-S-dPEG®₈-acid (QBD-10166)


Methoxytrityl-S-dPEG®8-acid is a discrete PEG (dPEG®) modification reagent that terminates in a propionic acid group on one end and a methoxytrityl-protected thiol on the other. The linker length is 28 atoms (32.5 Å). This product is useful for the thiolation of peptides and small molecules.


Methoxytrityl-S-dPEG®8-acid, product number QBD-10166, permits the introduction of a protected thiol-dPEG® spacer/linker onto a molecule by reaction with a free amine. The methoxytrityl (Mmt) protected thiol deprotects under relatively mild conditions using dilute trifluoroacetic acid (TFA) with a scavenger.

QBD-10166 permits our customers to insert a short (28 atoms, 32.5Å) dPEG® into a peptide chain using familiar solid phase or solution phase chemistry. The dPEG® can be inserted at the N-terminus of a peptide chain or on any amino acid side chain with an exposed free amine. In addition, the short dPEG® spacer can be used simply to provide additional 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 Mmt protecting group removes relatively easily with a dilute solution of TFA that also contains a scavenger such as triethylsilane (TES) or triisopropylsilane (TIPS). Once the thiol group is deprotected, it can be reacted with another thiol to form a disulfide bond or with any thiol-reactive group such as maleimide, bromoacetamide, alkene (thiol-ene reaction) or alkyne (thiol-yne reaction).

Upon activation, Methoxytrityl-S-dPEG®8-acid reacts with any free amine, whether on a peptide, surface, or other molecule. This allows for a broad range of applications where this product can be employed to convert an amine to a thiol.


Unit Size100 mg, 1000 mg
Molecular Weight730.91; single compound
Chemical formulaC₃₉H₅₄O₁₁S
Purity> 97%
SpacersdPEG® Spacer is 28 atoms and 32.5 Å
Typical solubility properties (for additional information contact Customer Support)Methylene chloride, Acetonitrile, 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.


  1. 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.

  2. Gold Nanoparticles Functionalized with Peptides for Specific Affinity Aggregation Assays of Estrogen Receptors and Their Agonists. Yoshiyuki Takatsuji, Shinya Ikeno and Tetsuya Haruyama. Sensors. 2012, 12 (4), pp 4952-4961. April 18, 2012. DOI: 10.3390/s120404952.

Applicable patents and legal notices are available at legal notices.

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