Mal-PEG4-Val-Cit-PAB-OH 是一种可降解 (cleavable) 的含 4 个单元 PEG 的 ADC linker，可用于合成抗体偶联活性分子 (ADC)。 Mal-PEG4-Val-Cit-PAB-OH is a cleavable ADC linker. The Val-Cit will specifically be cleaved by Cathepsin B. As this enzyme is only present in the lysosome, the ADC payload will be released only in the cell. The maleimide group is reactive toward thiol groups between pH 6.5 to 7.5. The hydroxyl group can be reacted to further derivatize the compound. The hydrophobic PEG chain increases the water solubility of the compound.