FMK-9a (FMK9a) is a potent, selective, covalent peptidomimetic inhibitor of ATG4B (Autophagin-1) with IC50 of 80 nM in TR-FRET assay.
FMK-9a displays no activity against the aspartic protease, serine proteases, metalloproteases and the 20S proteasome, inhibits cathepsin B and calpain with submicromolar IC50 (0.1-0.2 uM).
FMK-9a covalently binds to Cys74 and inactivates ATG4B proteolytic activity, has an IC50 of 15 nM in the cellular LRA assay.
