Vector Labs is closed to observe Independence Day (US Holiday) on Thursday, July 4th.
We will be back in the office on Friday. We will respond to emails upon our return. Have a wonderful day.

m-dPEG®₂₅-NHS ester (QBD-11291)



m-dPEG®25-NHS ester, product number QBD-11291, is a long (77 atoms, 89.9 Å), methyl-terminated, discrete-chain-length polyethylene glycol (dPEG®) spacer functionalized with an N-hydroxysuccinimidyl (NHS) ester for reaction with free amines. m-dPEG®25-NHS ester is just one member of an comprehensive line of methyl-terminated PEGylation reagents that includes dPEG® spacers containing 2 to 49 ethylene glycol units.

NHS esters react optimally with free amines at pH 7.0 – 7.5. In aqueous media, the hydrolytic rate of the ester to the carboxylic acid increases with increasing pH. Reacting surface amines on biomolecules (e.g., proteins and peptides) with this uncharged, methyl-capped dPEG® spacer may alter the overall charge of the resulting conjugates.

Many applications could employ m-dPEG®25-NHS ester, including the following:
dendrimer construction;
PK and immunogenicity improvements for dendrimers, peptides, and proteins;
cell surface engineering;
peptide synthesis and modification to improve water solubility or decrease immunogenicity;
coating of nanoparticles, quantum dots, and carbon nanotubes; and
prevention of protein aggregation.


Unit Size100 mg, 1000 mg
Molecular Weight1258.44; single compound
Chemical formulaC₅₆H₁₀₇NO₂₉
Purity> 98%
SpacersdPEG® Spacer is 77 atoms and 89.9 Å
Typical solubility properties (for additional information contact Customer Support)DCM, Methanol, Ethanol, Acetonitrile, Water, Ethyle Acetate, or Acetone.
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.

Applicable patents and legal notices are available at legal notices.

How do I Request a Quote?

To request a quote for products:

  1.  Sign in to
  2.  Add the items you wish to quote to the cart;
  3.  View your cart;
  4.  Click on the “Request a Quote” button found below the items in your cart;
  5.  Download your quote