Leupeptin is a competitive protease inhibitor produced by actinomycetes. Leupeptin can inhibit cysteine, serine and threonine peptidases. Leupeptin inhibits serine proteinases (trypsin (Ki=3.5 nM), plasmin (Ki= 3.4 nM), porcine kallikrein), and cysteine p
FD-IN-1 is a factor D (FD) inhibitor with an IC50 of 12 nM.FD-IN-1 also inhibits factor XIa (FXIa) and Tryptase β2 with IC50s of 7.7 and 6.5μM, respectively. Complement FD, a highly specific S1 serine protease, plays a central role in the alternative complement pathway of the innate immune system.