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Nepenthesin (and the carnivorous plants it comes from)

Nepenthesin (also spelled nepenthacin or nepenthasin) is an aspartic protease of plant origin that has so far been identified in the pitcher secretions of Nepenthes and in the leaves of Drosera peltata.

  1. Jentsch J (April 1972). “Enzymes from carnivorous plants (nepenthes). Isolation of the protease nepenthacin”. FEBS Lett. 21 (3): 273–276. doi:10.1016/0014-5793(72)80181-9. PMID 11946525.
  2. Jentsch J, Meierkord S, Hammer M (1989). “The enzymes from carnivorous plants (Nepenthes): Properties and characterization of the acid protease nepenthacin”. Planta Medica. 55 (2): 227. doi:10.1055/s-2006-961979.
  3. Nepenthesin. Integrated Enzyme Database (IntEnz).
  4. Amagase S, Nakayama S, Tsugita A (October 1969). “Acid protease in Nepenthes. II. Study on the specificity of nepenthesin”. J. Biochem. 66 (4): 431–9. doi:10.1093/oxfordjournals.jbchem.a129166. PMID 5354017.
  5. Amagase S (July 1972). “Digestive enzymes in insectivorous plants. 3. Acid proteases in the genus Nepenthes and Drosera peltata“. J. Biochem. 72 (1): 73–81. PMID 5069751.
  6. Amagase S, Mori M, Nakayama S (September 1972). “Digestive enzymes in insectivorous plants. IV. Enzymatic digestion of insects by Nepenthes secretion and Drosera peltata extract: proteolytic and chitinolytic activities”. J. Biochem. 72 (3): 765–7. PMID 4634982.
  7. Tökés ZA, Woon WC, Chambers SM (March 1974). “Digestive enzymes secreted by the carnivorous plant Nepenthes macferlanei L”. Planta. 119 (1): 39–46. doi:10.1007/BF00390820.
  8. Athauda SB, Inoue H, Iwamatsu A, Takahashi K (1998). “Acid Proteinase from Nepenthes distillatoria (Badura)”. In James, Michael (ed.). Aspartic proteinases: retroviral and cellular enzymes. New York: Plenum. pp. 453–458. ISBN 0-306-45809-8.
  9. Takahashi K, Tanji M, Shibata C (2007). “Variations in the content and isozymic composition of nepenthesin in the pitcher fluids among Nepenthes species” (PDF). Carnivorous Plant Newsletter. 36 (3): 73–76.

Discovery

In the late 19th century, Sydney Howard Vines showed that the pitcher fluid from Nepenthes could digest protein in acidic conditions. He suggested the plants were making a digestive enzyme, for which he proposed the name “nepenthin”. In the late 1960s, Josef Weigl’s group in Germany and Shizuko Amagase’s group in Japan each used chromatography to purify the proteolytic activity from several Nepenthes species, finding it to be most active at pH 2–3.  Amagase and Shigeru Nakayama proposed the name “Nepenthesin” for the responsible protease(s). In 1998, Kenji Takahashi’s group purified protein from 30 liters of Nepenthesia distillatoria fluid, finding activity similar to that previously described, and reporting part of the nepenthesin amino acid sequence.

  1. Frazier CK (June 2000). “The enduring controversies concerning the process of protein digestion in Nepenthes (Nepenthaceae)” (PDF). Carnivorous Plants Newsletter. 29: 56–61. Retrieved 1 September 2021.
  2. Steckelberg R, Lüttge U, Weigl J (September 1967). “[Purification of the proteinase from Nepenthes pitcher secretion]”. Planta (in German). 76 (3): 238–41. doi:10.1007/BF00409815. PMID 24549466.
  3. Nakayama S, Amagase S (1968). “Acid protease in Nepenthes: Partial purification and properties of the enzyme”. Proceedings of the Japan Academy. 44 (5): 358–362. doi:10.2183/pjab1945.44.358

INTERRUPTING THIS PAGE TO DISCUSS THESE BADASS PLANTS…IN FACT THEY WILL NEED THEIR OWN PAGES BUT UNTIL THEN…

  • Nepenthes  is a genus of carnivorous plants, also known as tropical pitcher plants, or monkey cups, in the monotypic family Nepenthaceae.  The name “monkey cups” refers to the fact that monkeys were once thought to drink rainwater from the pitchers. The name “monkey cups” was discussed in the May 1964 issue of National Geographic, in which Paul A. Zahl wrote:
    • The carriers called them “monkey cups,” a name I had heard elsewhere in reference to Nepenthes, but the implication that monkeys drink the pitcher fluid seemed farfetched. I later proved it true. In Sarawak, I found an orangutan that had been raised as a pet and later freed. As I approached it gingerly in the forest, I offered it a half-full pitcher. To my surprise, the ape accepted it, and with the finesse of a lady at tea, executed a delicate bottoms-up. Zahl, P.A. (1964). “Malaysia’s Giant Flowers and Insect-trapping Plants“. National Geographic. 125 (5): 680–701.
  • The genus name Nepenthes was first published in 1737 in Carl Linnaeus’s Hortus Cliffortianus. It references a passage in Homer’s Odyssey, in which the potion “Nepenthes pharmakon” is given to Helen by an Egyptian queen. “Nepenthe” literally means “without grief” (ne = not, penthos = grief) and, in Greek mythology, is a drug that quells all sorrows with forgetfulness. Linnaeus explained:
    • If this is not Helen’s Nepenthes, it certainly will be for all botanists. What botanist would not be filled with admiration if, after a long journey, he should find this wonderful plant. In his astonishment past ills would be forgotten when beholding this admirable work of the Creator! [translated from Latin by Harry Veitch] Veitch, H.J. (1897). “Nepenthes“. Journal of the Royal Horticultural Society. 21 (2): 226–262. Linnaeus, C. 1737. Nepenthes. Hortus Cliffortianus. Amsterdam. Gledhill, D. 2008. The Names of Plants. Fourth Edition. Cambridge University Press, Cambridge. Phillipps, A. & A. Lamb 1996. Pitcher-Plants of Borneo. Natural History Publications (Borneo), Kota Kinabalu.
    • The plant Linnaeus described was N. distillatoria, called bāndurā (බාඳුරා), a species from Sri Lanka. Nepenthes was formally published as a generic name in 1753 in Linnaeus’s famous Species Plantarum, which established botanical nomenclature as it exists today. Nepenthes distillatoria is the type species of the genus. The plants are often called kantong semar (Semar’s pocket) in Indonesia and sako ni Hudas (Judas’ money bag) in the Philippines. Phillipps, A. & A. Lamb 1996. Pitcher-Plants of Borneo. Natural History Publications (Borneo), Kota Kinabalu. Linnaeus, C (1753). “Nepenthes“. Species Plantarum. 2: 955.
  • N. bicalcarata provides space in the hollow tendrils of its upper pitchers for the carpenter ant Camponotus schmitzi to build nests. N. lowii has also formed a dependent relationship, but with vertebrates instead of insects. The pitchers of N. lowii provide a sugary exudate reward on the reflexed pitcher lid (operculum) and a perch for tree shrew species, which have been found eating the exudate and defecating into the pitcher. A 2009 study, which coined the term “tree shrew lavatories”, determined between 57 and 100% of the plant’s foliar nitrogen uptake comes from the faeces of tree shrews. Another study showed the shape and size of the pitcher orifice of N. lowii exactly match the dimensions of a typical tree shrew (Tupaia montana). A similar adaptation was found in N. macrophylla, N. rajah, N. ampullaria, and is also likely to be present in N. ephippiata. Similarly, N. hemsleyana, which is native to Borneo, has a symbiotic partnership with Hardwicke’s woolly bat. During the day, a bat may roost above the digestive fluid inside the pitcher. While a bat is inside, it may defaecate, and the plant can[vague] get nitrogen from the droppings. Clarke, C.M.; Bauer, U.; Lee, C.C.; Tuen, A.A.; Rembold, K.; Moran, J.A. (2009). “Tree shrew lavatories: a novel nitrogen sequestration strategy in a tropical pitcher plant“. Biology Letters. 5 (5): 632–635. doi:10.1098/rsbl.2009.0311. PMC 2781956. PMID 19515656. Chin, L.; Moran, J.A.; Clarke, C. (2010). “Trap geometry in three giant montane pitcher plant species from Borneo is a function of tree shrew body size“. New Phytologist. 186 (2): 461–470. doi:10.1111/j.1469-8137.2009.03166.x. PMID 20100203. Walker, M. 2010. Giant meat-eating plants prefer to eat tree shrew poo. BBC Earth News, March 10, 2010. Moran, J.A. (2003). “From carnivore to detritivore? Isotopic evidence for leaf litter utilization by the tropical pitcher plant Nepenthes ampullaria“. International Journal of Plant Sciences. 164 (4): 635–639. doi:10.1086/375422. hdl:10170/576. S2CID 53573745
  • Organisms that spend at least part of their lives within the pitchers of Nepenthes species are often called Nepenthes infauna. The most common infaunal species, often representing the top trophic level of the infaunal ecosystem, are many species of mosquito larvae. Other infaunal species include fly and midge larvae, spiders, mites, ants, and even a species of crab (Geosesarma malayanum). Many of these species specialise to one pitcher plant species and are found nowhere else. These specialists are called nepenthebionts. Others, often associated with but not dependent on Nepenthes species, are called nepenthophiles. Nepenthexenes, on the other hand, are rarely found in the pitchers, but will often appear when putrefaction approaches a certain threshold, attracting fly larvae that would normally not be found in the pitcher infaunal community. The complex ecological relationship between pitcher plants and infauna is not yet fully understood, but the relationship may be mutualistic: the infauna is given shelter, food, or protection, and the plant that harbours the infauna receives expedited breakdown of captured prey, increasing the rate of digestion and keeping harmful bacterial populations repressed. Mogi, M.; Yong, H.S. (1992). “Aquatic arthropod communities in Nepenthes pitchers: the role of niche differentiation, aggregation, predation and competition in community organization“. Oecologia. 90 (2): 172–184. Bibcode:1992Oecol..90..172M. doi:10.1007/BF00317174. PMID 28313712. S2CID 26808467. Beaver, R.A. (1979). “Fauna and foodwebs of pitcher plants in west Malaysia“. Malayan Nature Journal. 33: 1–10. Clarke, C.M. 1997. Nepenthes of Borneo. Natural History Publications (Borneo), Kota Kinabalu.
  • Nepenthes digestive fluids are sterile before pitchers open and contain secondary metabolites and proteins that act as bactericides and fungicides after the pitcher opens. While the digestive fluid is being produced, the pitcher is not yet open, so there is no chance of microbial contamination. During pitcher development, at least 29 digestive proteins including proteases, chitinases, pathogenesis-related proteins and thaumatin-like proteins are produced in the pitcher fluid. In addition to breaking down prey, these can act as antimicrobial agents. When the pitchers open, the fluid is exposed to bacteria, fungal spores, insects and rain. Often pitchers have a lid that covers the trap, excepting a few (e.g. N. lowii, N. attenboroughii and N. jamban), preventing rain water from entering. The lid inhibits rainwater from diluting the digestive fluid. Once the bacteria and fungi enter the fluid, secondary metabolites are produced in addition to antimicrobial proteins. Naphthoquinones, a class of secondary metabolite, are commonly produced, (Naphthoquinones constitute a class of organic compounds structurally related to naphthalene (as an aromatic hydrocarbon, naphthalene’s structure consists of a fused pair of benzene rings. It is best known as the main ingredient of traditional mothballs) and these either kill or inhibit the growth and reproduction of bacteria and fungi. This adaptation could have evolved since Nepenthes plants that could produce secondary metabolites and antimicrobial proteins to kill bacteria and fungi were most likely more fit. Plants that produced antimicrobial compounds could prevent loss of valuable nutrients gained from insects within the pitcher. Since Nepenthes cannot digest certain bacteria and fungi, the bactericides and fungicides allow plants to maximize nutrient uptake. Rottloff, Sandy; Miguel, Sissi; Biteau, Flore; Nisse, Estelle; Hammann, Philippe; Kuhn, Lauriane; Chicher, Johana; Bazile, Vincent; Gaume, Laurence (2016-03-01). “Proteome analysis of digestive fluids in Nepenthes pitchers“. Annals of Botany. 117 (3): 479–495. doi:10.1093/aob/mcw001. ISSN 0305-7364. PMC 4765550. PMID 26912512. Mithöfer, Axel (2011-09-01). “Carnivorous pitcher plants: Insights in an old topic“. Phytochemistry. Plant-Insect Interactions. 72 (13): 1678–1682. doi:10.1016/j.phytochem.2010.11.024. PMID 21185041. Buch, Franziska; Rott, Matthias; Rottloff, Sandy; Paetz, Christian; Hilke, Ines; Raessler, Michael; Mithöfer, Axel (2012-12-21). “Secreted pitfall-trap fluid of carnivorous Nepenthes plants is unsuitable for microbial growth“. Annals of Botany. 111 (3): 375–83. doi:10.1093/aob/mcs287. ISSN 0305-7364. PMC 3579442. PMID 23264234
  • interest in Nepenthes grew throughout the 19th century, culminating in what has been called the “Golden Age of Nepenthes” in the 1880s. Barthlott, W., Porembski, S., Seine, R., and Theisen, I. 2007. The Curious World of Carnivorous Plants. Portland, Oregon: Timber Press.  Phillipps, A. & A. Lamb 1996. Pitcher-Plants of Borneo. Natural History Publications (Borneo), Kota Kinabalu.
  • However, the popularity of the plants dwindled in the early 20th century, before all but disappearing by World War II. This is evidenced by the fact that no new species were described between 1940 and 1966. The revival of global interest in the cultivation and study of Nepenthes is credited to Japanese botanist Shigeo Kurata, whose work in the 1960s and 1970s did much to bring attention to these plants. Clarke, C.M. & C.C. Lee 2004. Pitcher Plants of Sarawak. Natural History Publications (Borneo), Kota Kinabalu.
  • See also:
  • Drosera peltata, commonly called the shield sundew or pale sundew, is a climbing or scrambling perennialtuberous species in the carnivorous plant genus Drosera. Members of the family Droseraceae lure, capture, and digest insects using stalked mucilaginous glands covering their leaf surfaces.
    •  Charles Darwin performed much of the early research into Drosera, engaging in a long series of experiments with Drosera rotundifolia which were the first to confirm carnivory in plants. In an 1860 letter, Darwin wrote, “…at the present moment, I care more about Drosera than the origin of all the species in the world.”
    • Both the botanical name (from the Greek δρόσος: drosos = “dew, dewdrops”) and the English common name (sundew, derived from Latin ros solis, meaning “dew of the sun”) refer to the glistening drops of mucilage at the tip of the glandular trichomes that resemble drops of morning dew. The Principia Botanica, published in 1787, states “Sun-dew (Drosera) derives its name from small drops of a liquor-like dew, hanging on its fringed leaves, and continuing in the hottest part of the day, exposed to the sun.”
    • Sundews were used as medicinal herbs as early as the 12th century, when an Italian doctor from the School of Salerno, Matthaeus Platearius, described the plant as an herbal remedy for coughs under the name herba sole. Culbreth’s 1927 Materia Medica listed D. rotundifolia, D. anglica and D. linearis as being used as stimulants and expectorants, and “of doubtful efficacy” for treating bronchitis, whooping cough, and tuberculosis. Sundew tea was recommended by herbalists for dry coughs, bronchitis, whooping cough, asthma and “bronchial cramps”. The French Pharmacopoeia of 1965 listed sundew for the treatment of inflammatory diseases such as asthma, chronic bronchitis and whooping cough. “Drosera herba“. Altmeyers Encyclopedia – Department Phytotherapy. 29 October 2020. Retrieved 17 March 2022. Culbreth, David M. R. (1927). Materia Medica and Pharmacology. Philadelphia: Lea & Febiger.Schilcher, H.; Elzer, M. (1993). “Drosera (Sundew): A proven antitussive“. Zeitschrift für Phytotherapie. 14 (50): 4. Ghate, N. B.; Das, A.; Chaudhuri, D.; Panja, S.; Mandal, N. (2016). “Sundew plant, a potential source of anti-inflammatory agents, selectively induces G2/M arrest and apoptosis in MCF-7 cells through upregulation of p53 and Bax/Bcl-2 ratio“. Cell Death Discovery. 2: 15062. doi:10.1038/cddiscovery.2015.62. ISSN 2058-7716. PMC 4979533. PMID 27551490. Retrieved 17 March 2022.
    • Modern studies have shown that Drosera exhibits antitussive and anti-inflammatory properties. It has been suggested that Drosera may stimulate the self-repair systems of bronchial epithelial cells to help resolve respiratory diseases. Drosera has been used commonly in cough preparations in Germany and elsewhere in Europe. Drosera is used to treat ailments such as asthma, coughs, lung infections, and stomach ulcers. It may also have anti-fertility properties. Ghate, N. B.; Das, A.; Chaudhuri, D.; Panja, S.; Mandal, N. (2016). “Sundew plant, a potential source of anti-inflammatory agents, selectively induces G2/M arrest and apoptosis in MCF-7 cells through upregulation of p53 and Bax/Bcl-2 ratio“. Cell Death Discovery. 2: 15062. doi:10.1038/cddiscovery.2015.62. ISSN 2058-7716. PMC 4979533. PMID 27551490. Retrieved 17 March 2022. Oliver-Bever, Bep (1986). Medicinal plants in tropical West Africa. Cambridge [Cambridgeshire]: Cambridge University Press. p. 129. ISBN 9780521105446. Paper, Dietrich H.; Karall, Elisabeth; Kremser, Michaela; Krenn, Liselotte (April 2005). “Comparison of the antiinflammatory effects ofDrosera rotundifolia andDrosera madagascariensis in the HET-CAM assay“. Phytotherapy Research. 19 (4): 323–326. doi:10.1002/ptr.1666. PMID 16041727. S2CID 20405232. Arruda-Silva, Fabio; Bellavite, Paolo; Marzotto, Marta (27 January 2021). “Low-dose Drosera rotundifolia induces gene expression changes in 16HBE human bronchial epithelial cells“. Scientific Reports. 11 (1): 2356. doi:10.1038/s41598-021-81843-y. ISSN 2045-2322. PMC 7840928. PMID 33504888. Retrieved 17 March 2022. “Sundew“. Kaiser Permanente. Retrieved 17 March 2022. Hoffmann, David (24 October 2003). Medical Herbalism: The Science and Practice of Herbal Medicine. Simon and Schuster. ISBN 978-1-59477-890-2. Retrieved 17 March 2022. Madhavan, V.; Hema Prem Kumar, Basnett; Murali, Anita; Yoganarasimhan, S.N. (1 February 2009). “Antifertility activity of Drosera burmannii“. Pharmaceutical Biology. 47 (2): 128–131. doi:10.1080/13880200802437149. ISSN 1388-0209. S2CID 85818974. Retrieved 17 March 2022.
    • Medicinal preparations are primarily made using the roots, flowers, and fruit-like capsules. Since all native sundews species are protected in many parts of Europe and North America, extracts are usually prepared using cultivated fast-growing sundews (specifically D. rotundifolia, D. intermedia, D. anglica, D. ramentacea and D. madagascariensis) or from plants collected and imported from Madagascar, Spain, France, Finland and the Baltics. Wichtl, M. (1994). Herbal drugs and phytopharmaceuticals : a handbook for practice on a scientific basis. Boca Raton, FL: CRC Press. p. 178, 81.
    • Sundews are historically mentioned as an aphrodisiac (hence the common name lustwort). Other anecdotal uses include strengthening the heart and treating sunburn and toothache. They are mentioned as a folk remedy for treatment of warts, corns, and freckles. Wolf, E.; Gage, E.; Cooper, D.J. (29 June 2006). “Drosera rotundifolia L. (roundleaf sundew): a technical conservation assessment” (PDF). USDA Forest Service, Rocky Mountain Region. Vogel, A. “Drosera rotundifolia L. | Round-leafed Sundew“. Plant Encyclopaedia. Retrieved 17 March 2022.Retrieved 17 March 2022. Ghosh, Dipanjan; Ghosh, Sreeparna (2016). “Drosera in danger” (PDF). Science Reporter. Retrieved 17 March 2022. Lewis, Walter H. (1977). Medical botany : plants affecting man’s health. St. Louis, Missouri: John Wiley & Sons. p. 254. ISBN 978-0471533207. Plant decoction of “Drosera sp.. used in Mexico to treat toothache. Crowder, A. A.; Pearson, M. C.; Grubb, P. J.; Langlois, P. H. (1990). “Drosera L.” Journal of Ecology. 78 (1): 233–267. doi:10.2307/2261048. ISSN 0022-0477. JSTOR 2261048. Retrieved 15 March 2022.
    • The mucilage produced by Drosera has remarkable elastic properties and has made this genus a very attractive subject in biomaterials research. In one recent study, the adhesive mucilages of three species (D. binata, D. capensis, and D. spatulata) were analyzed for nanofiber and nanoparticle content. Using atomic force microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy, researchers were able to observe networks of nanofibers and nanoparticles of various sizes within the mucilage residues. In addition, calcium, magnesium, and chlorine – key components of biological salts – were identified. These nanoparticles are theorized to increase the viscosity and stickiness of the mucilage, in turn increasing the effectiveness of the trap. More importantly for biomaterials research, however, is the fact that, when dried, the mucin provides a suitable substrate for the attachment of living cells. This has important implications for tissue engineering, especially because of the elastic qualities of the adhesive. Essentially, a coating of Drosera mucilage on a surgical implant, such as a replacement hip or an organ transplant, could drastically improve the rate of recovery and decrease the potential for rejection, because living tissue can effectively attach and grow on it. The authors also suggest a wide variety of applications for Drosera mucin, including wound treatment, regenerative medicine, or enhancing synthetic adhesives. Because this mucilage can stretch to nearly a million times its original size and is readily available for use, it can be an extremely cost-efficient source of biomaterial. Zhang, M.; Lenaghan, S.C.; Xia, L.; Dong, L.; He, W.; Henson, W.R.; Fan, X. (2010). “Nanofibers and nanoparticles from the insect capturing adhesive of the Sundew (Drosera) for cell attachment“. Journal of Nanobiotechnology. 8 (20): 20. doi:10.1186/1477-3155-8-20. PMC 2931452. PMID 20718990. Gaddam, Susmila Aparna; Kotakadi, Venkata Subbaiah; Subramanyam, Gunasekhar Kalavakunta; Penchalaneni, Josthna; Challagundla, Varadarajulu Naidu; Dvr, Sai Gopal; Pasupuleti, Visweswara Rao (9 November 2021). “Multifaceted phytogenic silver nanoparticles by an insectivorous plant Drosera spatulata Labill var. bakoensis and its potential therapeutic applications“. Scientific Reports. 11 (1): 21969. doi:10.1038/s41598-021-01281-8. ISSN 2045-2322. PMC 8578548. PMID 34753977. Retrieved 17 March 2022.
    • The corms of the tuberous sundews native to Australia are considered a delicacy by the Indigenous Australians.  Some of these corms were also used to dye textiles, while another purple or yellow dye was traditionally prepared in the Scottish Highlands using D. rotundifolia. A sundew liqueur is also still produced using a recipe from the 14th century. It is made using fresh leaves from mainly D. capensis, D. spatulata, and D. rotundifolia. Barthlott, Wilhelm; Porembski, Stefan; Seine, Rüdiger; Theisen, Inge (1 June 2004). Karnivoren Biologie und Kultur fleischfressender Pflanzen. Stuttgart (Hohenheim): Verlag Eugen Ulmer. ISBN 9783800141449. Yusuf, Mohd; Shabbir, Mohd; Mohammad, Faqeer (16 January 2017). “Natural Colorants: Historical, Processing and Sustainable Prospects“. Natural Products and Bioprospecting. 7 (1): 123–145. doi:10.1007/s13659-017-0119-9. ISSN 2192-2195. PMC 5315675. PMID 28093670. Plantarara (2001): Artzneimittle, Tee, und Likör aus fleischfressenden Pflanzen Archived 2006-06-18 at the Wayback Machine. Dwelly, Edward; “Dwelly’s [Scottish] Gaelic Dictionary” (1911) (Dath)

AND BACK TO THE ORIGINAL TOPIC (Nepenthesin)

Nepenthesin is similar to pepsin, but differs in that it also cleaves on either side of Asp residues and at Lys┼Arg. While more pH and temperature stable than porcine pepsin A, it is considerably less stable in urea or guanidine hydrochloride. It is the only known protein with such a stability profile.

  1. EC 3.4.23.12 – Nepenthesin. Integrated Enzyme Database (IntEnz).
  2. Kubota K, Metoki Y, Athauda SB, Shibata C, Takahashi K (2010). “Stability Profiles of Nepenthesin in Urea and Guanidine Hydrochloride: Comparison with Porcine Pepsin A”. Bioscience, Biotechnology, and Biochemistry. 74 (11): 2323–2326. doi:10.1271/bbb.100391.

The name nepenthesin was coined in 1968 by Shigeru Nakayama and Shizuko Amagase. Alternative names for this enzyme include Nepenthes acid proteinase and Nepenthes aspartic proteinase. Two isozymes have been identified in Nepenthes: nepenthesin I and nepenthesin II. The production of large quantities of nepenthesin-1 through heterologous expression in Escherichia coli was described in 2014.

  1. EC 3.4.23.12 – Nepenthesin. Integrated Enzyme Database (IntEnz).
  2. Nakayama S, Amagase S (1968). “Acid Protease in Nepenthes: Partial Purification and Properties of the Enzyme”. Proceedings of the Japan Academy. 44 (5): 358–362.[permanent dead link]
  3. Athauda SB, Matsumoto K, Rajapakshe S, Kuribayashi M, Kojima M, Kubomura-Yoshida N, Iwamatsu A, Shibata C, Inoue H, Takahashi K (July 2004). “Enzymic and structural characterization of nepenthesin, a unique member of a novel subfamily of aspartic proteinases”. Biochem. J. 381 (Pt 1): 295–306. doi:10.1042/BJ20031575. PMC 1133788. PMID 15035659.

The names cephalotusin, dionaeasin and droserasin have been proposed for similar aspartic endopeptidases originating from the carnivorous plant genera Cephalotus, Dionaea and Drosera, respectively.

  1. Frazier CK (June 2000). “The enduring controversies concerning the process of protein digestion in Nepenthes (Nepenthaceae)” (PDF). Carnivorous Plants Newsletter. 29: 56–61. Retrieved 1 September 2021.

External links

  • The MEROPS online database for peptidases and their inhibitors: A01.040
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