Mal-PEG4-Val-Cit-PAB-PNP is a cleavable ADC linker. The Val-Cit linkers can be cleaved by Cathepsin B. Maleimide (Mal) group is reactive toward thiol groups. PEG space improve compound's aqueous solubility. PNP is a good leaving group. Reagent grade, for research purpose. Please contact us for GMP-grade inquiries.