Lipoamide-PEG11-Mal contains the functional form of lipoic acid, lipoamide, via an amide bond and a maleimide end group. The lipoic acid is a co-factor that is used in biological systems such as the citric acid cycle. Maleimides are thiol-reactive between pH 6.5 to 7.5 and form thioester bonds. The hydrophilic PEG linkers increase the water solubility of compounds in aqueous media. The water solubility properties of the PEG linker are enhanced with longer PEG chains.