SSM3 tetraTFA hydrate, a potent synthetic inhibitor of furin, exhibits an EC50 of 54 nM and a Ki of 12 nM, effectively inhibiting the furin-dependent cell surface processing of anthrax protective antigen-83 in vitro [1] [2].

SSM3 tetraTFA hydrate effectively inhibits furin-mediated cleavage, exhibiting an EC50 value of 54 nM for the Pyr-RTKR-AMC substrate in both in vitro assays and cell-based tests [2]. It also dose-dependently prevents the furin-dependent conversion of PA83 to PA63 in cleavage reactions, with concentrations ranging from 0.1-25 μM [2]. The compound demonstrates comparable inhibitory potency against furin (Ki = 0.012 μM) and PC6B (Ki = 0.004 μM), with a preference for furin over PACE4 by 2- to 10-fold (Ki = 0.041 μM) and over PC7 by 11- to 76-fold (Ki = 0.595 μM). While SSM3 tetraTFA hydrate is less effective against LF (Ki = 1.241 μM) by 25- to 167-fold compared to furin, it does not significantly inhibit trypsin and MT1-MMP [2].