ML-323

ML-323 is a reversible, potent USP1-UAF1 inhibitor with IC₅₀ of 76 nM in a Ub-Rho assay. The measured inhibition constants of ML-323 for the free enzyme (K_i) is 68 nM. IC50 & Target: IC50: 76 nM (USP1-UAF1, in Ub-Rho assay)^[1]
Ki: 68 nM (USP1-UAF1)^[1] In Vitro: ML-323 (ML323) is a highly potent inhibitor of the USP1-UAF1 deubiquitinase complex with excellent selectivity against human DUBs, deSUMOylase, deneddylase and unrelated proteases. ML-323 is a potent USP1-UAF1 inhibitor with IC50 values of 76 nM in a ubiquitin-rhodamine (Ub-Rho) assay and 174 nM and 820 nM in orthogonal gel-based assays using K63-linked diubiquitin (di-Ub) and monoubiquitinated PCNA (Ub-PCNA) as substrates, respectively. ML-323 probably exerts its inhibitory effect through an allosteric mechanism. The measured inhibition constants of ML-323 for the free enzyme (K_i) and the enzyme-substrate complex (K’_i) are 68 nM and 183 nM. Besides, ML-323 potentiates Cisplatin cytotoxicity in non-small cell lung cancer and osteosarcoma cells^[1]. ML-323 (ML323), a probe molecule that displays reversible, nanomolar inhibitory activity and excellent selectivity toward USP1/UAF1. In addition, ML-323 potentiates the cytotoxicity of Cisplatin and increases endogenous monoubiquitination levels of both PCNA and FANCD2, two known cellular targets of USP1/UAF1^[2].