A nonselective inhibitor of UBL protein-activating E1 enzymes that forms covalent adducts with UBL proteins SUMO1, ubiquitin, Nedd8, ISG15, and GABARAP in the presence of ATP and E1 enzymes in vitro.

A potent, covalent inhibitor of ubiquitin-conjugating enzyme UbcH5 with Kd of 5.189 uM, 3.578 uM, and 2.577 uM for UbcH5a, UbcH5b, and UbcH5c, respectively.

A potent, specific, orally bioactive small-molecule inhibitor of ubiquitin-conjugating enzyme UbcH5c with Kd of 283 nM.

ABP-A3(ABP A3) is an inhibitor of ubiquitin conjugation that targets ubiquitin and Nedd8 E1 enzymes.

PYR-41 is a specific and cell permeable inhibitor of ubiquitin-activating enzyme E1 with an IC50 of < 10 uM, with no or little activity at E2.

PYZD-4409 is a novel small molecule inhibitor of Ubiquitin-activating enzyme UBA1/E1 enzyme with an IC50 of 20 uM (cell-free enzymatic assay).

TAK-243 (MLN-7243, AOB87172) is a small-molecule, cell-permeable inhibitor of ubiquitin-activating enzyme E1 (UAE1).

Ubiquitination-IN-1 (compound 24) is a ubiquitination and Cksl-Skp2 protein-protein interaction (IC50=0.17 μM) inhibitor. Ubiquitination-IN-1 increases levels of p27. Ubiquitination-IN-1 has the potential for treatment disease by blocking the degradation of tumor suppressors.