m-dPEG®₂₅-amido-dPEG®₂₄-TFP ester

m-dPEG®25-amido-dPEG®24-TFP ester, product number 11096, is a long, methyl-terminated, discrete length polyethylene glycol (dPEG®) spacer. The reactive end of the product is a 2,3,5,6-tetrafluorophenyl (TFP) ester. An amide bond joining two PEG subunits is in the center of the molecule. m-dPEG®25-amido-dPEG®24-TFP ester is designed to modify surfaces containing available free amines. This product is a much longer version of m-dPEG®12-amido-dPEG®12-TFP ester, product number 10149.

Free amines react optimally with TFP esters at pH 7.5 – 8.0 in aqueous media. Compared to N-hydroxysuccinimidyl (NHS) esters, TFP esters are more hydrolytically stable in water and aqueous buffer. Nevertheless, in aqueous media, the rate at which the ester hydrolyzes to the carboxylic acid increases as the pH increases. Consequently, we do not recommend storage of this product in aqueous media. Moreover, please note that reacting free amines on biomolecules with this uncharged, methyl-capped dPEG® spacer may alter the overall charge of the resulting conjugates.

Many applications potentially, successfully could use m-dPEG®25-amido-dPEG®24-TFP ester to improve performance and function. Among those applications are:

cell surface engineering;
PK, BD, and immunogenicity profile improvements for biomolecules;
imaging applications to reduce non-specific binding and background;
dendrimer construction;
nanoparticle, quantum dot, and carbon nanotube surface coating; and,
prevention of protein aggregation.

m-dPEG®25-amido-dPEG®24-TFP ester, product number 11096, is just one member of an extensive line of methyl-terminated dPEG® products. This line includes dPEG® spacers containing 2 to 49 ethylene glycol units. These products terminate with a carboxylic acid group, which may be activated with NHS or TFP. In addition to better stability to hydrolysis, TFP esters have proven to be superior to NHS esters for amine-reactive products.

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