From the insectivorous plants Nepenthes spp. (secretions) and Drosera peltata (ground-up leaves). Aspartic endopeptidases are probably present in many other plants, including Lotus  and sorghum . In peptidase family A1 (pepsin A family)
Amagase, S., Nakayama, S. and Tsugita, A. Acid protease in Nepenthes. II. Study on the specificty of nepenthesin. J. Biochem. (Tokyo)66 (1969) 431–439. [PMID: 5354017]
Garg, G.K. and Virupaksha, T.K. Acid protease from germinated sorghum. 2. Substrate specificity with synthetic peptides and ribonuclease A. Eur. J. Biochem.17 (1970) 4–12. [DOI] [PMID: 5486576]
Shinano, S. and Fukushima, K. Studies on lotus seed protease. Part III. Some physicochemical and enzymic properties. Agric. Biol. Chem.35 (1971) 1488–1494.
Amagase, S. Digestive enzymes in insectivorous plants. III. Acid proteases in the genus Nepenthes and Drosera peltata. J. Biochem. (Tokyo)72 (1972) 73–81. [PMID: 5069751]
Takahashi, K., Chang, W-J. and Ko, J-S. Specific inhibition of acid proteases from brain, kidney, skeletal muscle, and insectivorous plants by diazoacetyl-DL-norleucine methyl ester and by pepstatin. J. Biochem. (Tokyo)76 (1974) 897–899. [PMID: 4436292]
Tökés, Z.A., Woon, W.C. and Chambers, S.M. Digestive enzymes secreted by the carnivorous plant Nepenthes macferlani L. Planta119 (1974) 39–46. [DOI] [PMID: 16526095]
[EC 18.104.22.168 created 1972 as EC 22.214.171.124, transferred 1978 to EC 126.96.36.199, modified 1981]