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Thermo Scientific™ Pierce™ Methyl-PEG-Maleimide Reagents

Pegylate sulfhydryls (-SH groups) on proteins (cysteine residues) or assay surfaces using MS(PEG); sulfhydryl-reactive (maleimide), PEG compounds (12 and 24 EG units).

Manufacturer: thermo scientific™  22711

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Catalog No. PI22711


Description & Specifications


Capping Group Methyl
Chemical Reactivity Sulfhydryl
Cleavable No
Description Pierce MM(PEG)12
Formulation 12-unit ethyleneglycol functionalized with methyl and maleimido ends; solid
Molecular Weight 710.81
PEGylated Yes
Quantity 100mg
Sufficient For 141mL of typical 1X (1mM) reaction solution, or approx. 50 uses at 2mg reagent per use
Spacer Arm Length 51.9Å

Thermo Scientific™ Pierce MM(PEG)12 is a methyl-terminated, polyethylene glycol compound (3 times 12 PEG units) activated with a maleimide group for covalent pegylation of sulfhydryls on proteins (e.g., cysteines) or assay surfaces.

MM(PEG)n is the abbreviation for a set of compounds having polyethylene glycol (PEG) spacers with methyl (—CH3) and sulfhydryl-reactive maleimide groups at opposite ends. The unbranched, hydrophilic, discrete-length molecules have the form Methyl-PEGn-Maleimide, where the subscript “n” denotes 12 or 24 ethylene glycol units. The maleimide is spontaneously reactive with sulfhydryl (—SH) groups, providing for efficient PEGylation of proteins, peptides and other cysteine- or thiol-containing molecules.


  • Maleimide-activated for efficient PEGylation of sulfhydryl groups at pH 6.5-7.5; reaction of maleimide group results in formation of stable, irreversible thioether bonds
  • Fully characterized PEGylation reagents with defined PEG chain lengths; molecules of discrete molecular weight for consistency of performance in protein-modification applications
  • Provided with either 12 or 24 ethylene glycol units, enabling modification procedures to be optimized for a specific application while retaining all the benefits associated with protein PEGylation
  • 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