Protease Cleavable Linker

Protease-cleavable linkers connect targeting units to payloads and enable conditional drug release after protease processing in ADCs and related drug conjugates[1]. Mechanistically, Val-Cit and related peptide linkers support lysosomal cathepsin-mediated payload release, while plasma stability remains a central design requirement[1][2]. In tumor models, cleavable Val-Cit or Val-Ala systems released MMAE after intracellular or extracellular proteolysis and produced antitumor activity, whereas noncleavable designs reduced activity in comparable settings[3][4]. Compared with Val-Cit, Val-Ala, glutamic acid-Val-Cit, EGCit, and exo-cleavable designs addressed isoform-like sequence differences in linker susceptibility, including mouse carboxylesterase, neutrophil elastase, aggregation, and premature release[2][5][6][7]. For research applications, these linkers guide ADC, albumin-drug conjugate, and immune-stimulating antibody conjugate design by balancing protease access, tumor payload release, plasma stability, and species-relevant preclinical evaluation[6][8][9].
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