Update profile
    Change password
    Sign out

Our content has moved! Check out our protein biology page on lifetechnologies.com  Go now >

Methyl-PEG-NHS-Ester Branched Reagents

NHS-ester activated for three-branched pegylation of primary amines.

Pierce TMS(PEG)12

Thermo Scientific Pierce TMS(PEG)12 is a three-branched, polyethylene glycol compound (3 times 12 PEG units) activated as an NHS ester for covalent pegylation of primary amines (e.g., lysines) on proteins or assay surfaces.

TMS(PEG)12 is the abbreviation for a branched trimethyl (TM) and succinimide ester (S) derivative of polyethylene glycol (PEG) for efficient and specific modification of primary amines. Each methyl-terminated PEG (mPEG) branch contains 12 ethylene glycol units. The three branches are attached to a 4-unit PEG stem that contains an amine-reactive N-hydroxysuccinimide (NHS) ester at the distal end. The NHS ester is spontaneously reactive with primary amines (–NH2), providing for efficient PEGylation of proteins, peptides and other amine-containing molecules or surfaces.


  • NHS-activated for efficient PEGylation of primary amines at pH 7-9; reaction of NHS-ester group results in formation of stable, irreversible amide bonds
  • Pure compound with defined structure and molecular weight, ensuring reproducible protein-modification effects
  • PEG spacer provides unique advantages, including increased stability, reduced tendency toward aggregation and reduced immunogenicity
  • Easy-to-follow instructions increase the likelihood of a successful outcome

Product Details:

General structure of TMS(PEG)12, a branched, NHS-activated PEGylation Reagent
Complete structure of TMS(PEG)12, a branched, NHS-activated PEGylation Reagent
Chemical structure of Trimethyl-PEG-NHS Ester reagent, TMS(PEG)12. Alternative names include (Methyl-PEG12)3-PEG4-NHS Ester; Branched mPEG-NHS Ester; Trimethyl-PEO-NHS Ester; NHS-activated PEG 2000.

PEGylation Applications:

  • PEGylate amine surfaces
  • Add inert mass to proteins, immunogens, drug compounds and probes
  • Improve solubility (decrease aggregation) of proteins or peptides without affecting function
  • Protect proteins from proteolysis

Why PEGylate a protein or peptide?

PEG-containing reagents have been used to modify proteins to provide specific advantages. Protein PEGylation can improve the stability of the modified protein, protect it from proteolytic digestion, increase its half life in biological applications, mask it from causing an immunogenic response, decrease its antigenicity or potential toxicity, improve its solubility, diminish the potential for aggregation, and minimize interference for both in vitro and in vivo applications. Polyethylene glycol, also called polyethylene oxide (PEO), has these effects because it is nontoxic, nonimmunogenic, hydrophilic, water soluble and highly flexible.

TMS(PEG)12 is specially synthesized as a homogeneous compound of discrete chain length and defined molecular weight. By contrast, typical preparations of PEG compounds are heterogeneous mixtures composed of multiple chain lengths and a range of molecular weights.


  1. Hermanson, G.T. (2008). Bioconjugate Techniques, Academic Press. (Part No. 20036)
  2. Harris, J. M. and Zalipsky, S. Eds (1997). Poly(ethylene glycol), Chemistry and Biological Applications, ACS Symposium Series, 680.
  3. Harris, J. M. and Kozlowski, A. (2001). Improvements in protein PEGylation: pegylated interferons for treatment of hepatitis C. J. Control Release 72, 217-224.
  4. Veronese, F. and Harris, J.M. Eds. (2002). Peptide and protein PEGylation. Advanced Drug Delivery Review 54(4), 453-609.

Related Products:

Protein PEGylation technical guide (and PEG reagent selection guide)
Linear NHS-activated PEG Reagents, MS(PEG)n

Ordering Information
Product # Description Pkg. Size Instructions MSDS CofA Price
22424 TMS(PEG)12
Formulation: 4-unit ethyleneglycol functionalized with a succinimidyl end and three methyl-terminated, 12-unit ethyleneglycol arms; waxy solid
Sufficient For: 410mL of typical 1X (1mM) reaction solution
1g Product Instructions for product #22424 TMS(PEG)12 MSDS for product #22424 TMS(PEG)12 Certificate of Analysis for product #22424 TMS(PEG)12 $1,497.00

Now available on lifetechnologies.com

Instructions | MSDS | CofA
Product Instructions | MSDS | CofA  

Recommend this page

Follow Us
Email Sign-up  Email Announcements

You may also need
23227 - BCA Protein Assay Kit

23235 - Micro BCA Protein Assay Kit

34075 - SuperSignal West Dura Extended Duration Substrate

77159 - Imject Purification Buffer Salts

78503 - M-PER Mammalian Protein Extraction Reagent


Antibodies  |   Molecular Biology   |   Cell Biology   |  Thermo Scientific  |   * Trademarks  |   Privacy Statement
© 2015 Thermo Fisher Scientific Inc.   |   3747 N Meridian Rd, Rockford, IL USA 61101   |   1-800-874-3723  or  815-968-0747