Bis-Mal-Lysine-PEG4-acid is a PEG linker with two maleimide groups which can react with thiols from pH ranges of 6.5 to 7.5 to from a thiolester bond. The terminal carboxylic acid can react with primary amines in the presence of activators such as EDC and HATU to form stable amide bonds. The hydrophilic PEG linker increases the water solubility of a compound in aqueous media.
