m-dPEG®₁₂-amido-dPEG®₁₂-TFP ester

m-dPEG®12-amido-dPEG®12-TFP ester is a long, methyl-terminated, discrete length polyethylene glycol (dPEG®) spacer. The reactive end of the molecule is a 2,3,5,6-tetrafluorophenyl (TFP) ester. An amide bond joining two discrete PEG subunits is in the center of the molecule. m-dPEG®12-amido-dPEG®12-TFP ester is designed to modify surfaces containing accessible free amines. This product is similar to m-dPEG®24-TFP ester, product number 10303. However, it is slightly longer than PN10303, and the central amide bond in PN10149 slightly alters the spacer's flexibility.

Free amines react optimally with TFP esters at pH 7.5 – 8.0 in aqueous media. TFP esters are more hydrolytically stable in water and aqueous buffer than NHS esters. Nevertheless, in aqueous media, the rate at which the ester hydrolyzes to the carboxylic acid increases as the pH increases. Moreover, it should be noted that 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 potentially, successfully use m-dPEG®12-amido-dPEG®12-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®12-amido-dPEG®12-TFP ester, product number 10149, is just one member of a broad line of methyl-terminated dPEG® products. This line includes dPEG® spacers containing 2 to 49 ethylene glycol units. These products are functionalized 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.

Quanta BioDesign, Ltd., makes and sells single molecular weight PEG linkers and spacers with discrete chain lengths under the trade name dPEG®. Our products are distinctly different from traditional PEG products in that they are not disperse polymers. However, they confer all of the benefits of traditional PEG products.

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