MAL-dPEG®₂₄-amido-dPEG®₂₄-TFP ester

MAL-dPEG®24-amido-dPEG®24-TFP ester, product number 11303, is a monodisperse, crosslinking PEGylation reagent that joins sulfhydryl groups to amines through a single molecular weight, discrete PEG (dPEG®) chain. At pH 6.5 – 7.5, the maleimido group reacts specifically with sulfhydryl (thiol) groups to form a thioether bond. The 2,3,5,6-tetrafluorophenyl (TFP) ester reacts with free amines to form amide bonds. Compared with N-hydroxysuccinimide (NHS) esters, TFP esters are more reactive and hydrolytically stable in aqueous buffer. The water-soluble, nonimmunogenic dPEG® spacer increases the hydrophilicity and hydrodynamic volume of conjugates made with this product.

Crosslinking Reactions with PEGylation Reagents
One of the most popular, most useful crosslinking reactions in bioconjugate chemistry is the conjugation of free amines to free thiols. These reactions require heterobifunctional reagents that bridge the two groups. Typical crosslinkers are short and hydrophobic. Our dPEG® crosslinking products are water-soluble, amphiphilic, single molecular weight PEG compounds with discrete chain lengths.

Conventional hydrophobic crosslinking reagents frequently trigger aggregation and precipitation of the conjugates made from them. Moreover, these hydrophobic crosslinkers may contribute to non-specific binding problems in some assays. These problems do not happen with our water-soluble, non-immunogenic dPEG® crosslinkers.

Traditional PEGylation reagents are made from dispersed polymers. These polymeric reagents are intractably complex mixtures of different PEG chain lengths and molecular weights. This complexity creates difficulties in the analysis of conjugates. Our dPEG® products have no dispersity (Ð = 1). Each dPEG® product consists of a discrete chain of PEG with a single molecular weight. The uniform nature of our dPEG® products eliminates one of the most vexing analytical difficulties faced by users of traditional polymer PEG products.

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