Organic Chemical
ricin
ri·cin [ rahy-sin, ris-in ]
Subclass of:
Plant Lectins;
Albumins
Definitions related to ricin:
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A phytotoxin and lectin comprised of a homodimer of ricin toxin A and B chains derived from the seeds of Ricinus communis, the castor oil plant, with protein synthesis inhibitory activity and extremely high cytotoxicity. Following ingestion, inhalation or injection of ricin, the B chain binds to complex carbohydrates containing either terminal N-acetylgalactosamine or beta-1,4-linked galactose residues on the surface of cells. Subsequently, the ricin A/B heterodimer is internalized and undergoes retrograde transport to the endoplasmic reticulum (ER). In the ER, the A chain, which has enzymatic activity that is sterically hindered by the B chain, is proteolytically released from the heterodimer by protein disulfide isomerase. In the ER, the free A chain has N-glycosidase activity that cleaves 28S rRNA. This enzymatic cleavage disrupts the ribosome, halts protein synthesis, and can lead to cell death. The extreme cytotoxicity of ricin makes it an attractive candidate for artificial fusion with binding proteins to create cell-type-specific toxins.NCI ThesaurusU.S. National Cancer Institute, 2021
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A protein phytotoxin from the seeds of Ricinus communis, the castor oil plant. It agglutinates cells, is proteolytic, and causes lethal inflammation and hemorrhage if taken internally.NLM Medical Subject HeadingsU.S. National Library of Medicine, 2021
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Proteinaceous phytotoxin from the castor oil plant, Ricinus communis; A chain has glycosidase activity which cleaves 28S rRNA, halting protein synthesis; extreme cytotoxicity makes ricin an attractive candidate for artificial fusion with binding proteins to create cell-type-specific toxins.CRISP ThesaurusNational Institutes of Health, 2006
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Ricin, toxic protein (toxalbumin) occurring in the beanlike seeds of the castor-oil plant (Ricinus communis). Ricin, discovered in 1888 by German scientist Peter Hermann Stillmark, is one of the most toxic substances known. It is of special concern because of its potential use as a biological...Encyclopedia Britannica, Inc., 2020
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