PR-619 is a broad-spectrum and reversible inhibitor of the deubiquitinylating enzymes (DUBs) with EC50 of 1-20 μM and it was developed for chemotherapy.

TCID is a DUB inhibitor for ubiquitin C-terminal hydrolase L3 with IC50 of 0.6 μM, 125-fold selective to L1.

LDN-57444 is a reversible inhibitor of UCHL1 with IC50 of 0.88 μM (Ki = 0.4 μM) and its selectivity is better than UCH-L3 (IC50 = 25 μM).

b-AP15 is an inhibitor of the ubiquitin carboxyl-terminal hydrolase isozyme L5 (UCHL5) and ubiquitin-specific-processing protease 14 (USP14). In purified 19S proteasomes, b-AP15 can inhibit DUB activity with an IC50 of 2.1 μM.