PfSUB1-IN-1 (compound 4c) is a plasmodium falciparum subtilisin-like serine protease 1 ( PfSUB1 ) Inhibitor ( IC 50 : 15 nM).PfSUB1 is an antimalarial target. PfSUB1-IN-1 inhibits the growth of a genetically modified P. falciparum line expressing reduced levels of PfSUB1 13-fold more efficiently compared to a wild-type parasite line.