MAL-dPEG®₆-TFP ester

MAL-dPEG®6-TFP ester, product number 10556, is a crosslinking reagent built around a polyethylene glycol (PEG) cross-bridge. This product joins free amines to free thiols (sulfhydryl groups). Sulfhydryl groups react with the maleimide via a Michael addition reaction. The amines form amide bonds with the crosslinker by nucleophilic substitution of the 2,3,5,6-tetrafluorophenyl (TFP) ester of the terminal propionic acid group. The maleimido and TFP functional groups of the crosslinker sit at either end of a short, discrete-length chain of PEG (hence, dPEG®).

Crosslinking Reactions
The conjugation of free amines to sulfhydryl groups is one of the most popular, most useful crosslinking reactions in bioconjugate chemistry[1],[2]. These reactions require heterobifunctional reagents capable of bridging the two groups. Typical crosslinkers are hydrophobic. Our amphiphilic dPEG® PEGylation reagents are monodisperse, single molecular weight PEG compounds with discrete chain lengths.

Conventional hydrophobic crosslinking reagents frequently trigger aggregation and precipitation of the conjugates made from them. These problems do not happen with our water-soluble, non-immunogenic dPEG® crosslinkers. Furthermore, hydrophobic crosslinkers contribute to non-specific interactions in assays. Our dPEG® PEGylation reagents greatly reduce and often eliminate non-specific interactions due to hydrophobicity.

Traditional PEGylation reagents are made from dispersed polymers. These polymeric reagents are intractably complex mixtures of different sizes and molecular weights of PEG chains. This complexity creates difficulties in the analysis of conjugates. Our dPEG® products have no dispersity (Ð = 1; that is, they are monodisperse PEGs). 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.

Nevertheless, our customers enjoy all the benefits of PEG, minus the headaches that PEG polymers cause.

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