Used in solid-phase peptide synthesis as a protected tripeptide building block, particularly in the preparation of antibody-drug conjugates (ADCs). The Aloc (allyloxycarbonyl) groups serve as orthogonal protecting groups that can be selectively removed under mild conditions, allowing stepwise peptide assembly. The PAB (para-aminobenzyl) linker acts as a spacer and is commonly employed as a self-immolative linker in prodrug and ADC design. Upon enzymatic cleavage, the PAB-PNP moiety releases active payloads, making this compound valuable in the development of targeted therapeutics, especially in cancer drug delivery systems where controlled release is critical.