Lipoamido-PEG4-acid contains a lipoic acid group and a terminal carboxylic acid. Lipoic acid contains two sulfur atoms (at C6 and C8) connected by a disulfide bond and is thus considered to be oxidized although either sulfur atom can exist in higher oxidation states. The terminal carboxylic acid can react with primary amine groups in the presence of activators (e.g. EDC, or HATU) to form a stable amide bond. The hydrophilic PEG linker increases the water solubility of the compound.
