PSI-7409 tetrasodium is an active 5'-triphosphate metabolite of sofosbuvir (PSI-7977)(IC50s of 1.6, 2.8, 0.7 and 2.6 μM for GT 1b_Con1, GT 2a_JFH1, GT 3a, and GT 4a NS5B polymerases, respectively).
MP-1 is a covalent inhibitor of fumarate hydratase (FH) that exhibits cytotoxicity dependent on FH. MP-1 engages a functional cysteine in the Zn-finger domain of the tRNA methyltransferase enzyme TRMT1.