Pepstatin Trifluoroacetate (Pepstatin A), a specific and orally active aspartic protease inhibitor produced by actinomycetes, demonstrates inhibition efficacy with IC50 values of 4.5 nM, 6.2 nM, 150 nM, 290 nM, 520 nM, and 260 nM against hemoglobin-pepsin, hemoglobin-proctase, casein-pepsin, casein-proctase, casein-acid protease, and hemoglobin-acid protease, respectively. Additionally, it effectively inhibits HIV protease.