Title: Abrin
CAS Registry Number: 1393-62-0
Additional Names: Agglutinin; toxalbumin
Literature References: A toxic lectin and hemagglutinin obtained from seeds of jequirity, Abrus precatorius L., Leguminosae, a common vine of tropical countries, also found in central and southern Florida. Isoln and purification: J. Y. Lin et al., J. Formosan Med. Assoc. 68, 518 (1969), C.A. 72, 98695 (1970); eidem, Toxicon 9, 97 (1971). The high toxicity of abrin was originally believed to result from its hemagglutinating activity, but subsequent studies have shown that separate proteins are responsible for the toxicity and agglutination: S. Olsnes, A. Pihl, Eur. J. Biochem. 35, 179 (1973). Five glycoproteins have been purified from the seeds of A. precatorius: Abrus agglutinin and the toxic principles, abrins a-d. Abrus agglutinin is a tetramer of 134,900 Da, is non-toxic to animal cells and a potent hemagglutinator. Abrins a through d (mol wt 63,000-67,000 Da) are composed of two disulfide-linked polypeptide chains. The smaller A-chain inhibits protein synthesis and causes cell death; the larger B-chain binds to the cell plasma membrane. Purification of major components: C. H. Wei et al., J. Biol. Chem. 249, 3061 (1974). Crystallographic study: C. H. Wei, J. R. Einstein, ibid. 2985. Improved purification, properties, crystallography of Abrus agglutinin: C. H. Wei et al., ibid. 250, 4790 (1975). Physical properties of the toxic principles: M. S. Herrmann, W. D. Behnke, Biochim. Biophys. Acta 621, 43 (1980); eidem, ibid. 667, 397 (1981). Isoln and purification of all five proteins: J. Y. Lin et al., Toxicon 19, 41 (1981). Amino acid sequence of the A-chain of abrin-a and comparison with ricin: G. Funatsu et al., Agric. Biol. Chem. 52, 1095 (1988). Antitumor effects in animals: V. V. S. Reddy, M. Sirsi, Cancer Res. 29, 1447 (1969); J. Y. Lin et al., Nature 227, 292 (1970); O. Fodstad et al., Cancer Res. 37, 4559 (1977). Immunoelectron microscopy studies of abrin toxic action on tumor cells: C. T. Lin et al., J. Ultrastruct. Res. 73, 310 (1980). Studies on toxicity and binding kinetics: M. Witten et al., Exp. Cell Biol. 49, 306 (1981); C. E. Bennett et al., ibid. 319. Use of A-chain in cell-type-specific cytotoxic agents known as "immunotoxins": A. J. Cumber et al., Methods Enzymol. 112, 207 (1985). Toxicity study: J. Y. Lin et al., J. Formosan Med. Assoc. 68, 322 (1969), C.A. 71, 121926 (1969). See also Ricin, Lectins.
Properties: Yellowish-white powder. Sol in solns of sodium chloride, usually with turbidity. The toxic portion is heat-stable to incubation at 60° for 30 min; at 80°, most of the toxicity is lost in 30 min. LD50 i.p. in mice: 0.020 mg/kg (Lin p. 322).
Toxicity data: LD50 i.p. in mice: 0.020 mg/kg (Lin p. 322)
CAUTION: Seeds of A. precatorius are extremely toxic; one seed, if thoroughly masticated, can cause fatal poisoning, cf. J. M. Kingsbury, Poisonous Plants of the United States and Canada (Prentice-Hall, New Jersey, 1964) p 303; K. Genest et al., Arzneim.-Forsch. 21, 888 (1971). Note: Do not confuse with abrine, q.v.
Use: Exptly in cancer research.
Abrine Acacic Acid Acadesine Acamprosate Calcium Acarbose

Jequirity, the source plant of abrin

Abrin is a toxalbumin (with an LD50 of 0.7 µg/kg of body mass when given to mice intravenously,[1] and 10–1000 µg/kg when ingested by humans and 3.3μg/kg when inhaled by humans[2]) that is found in the seeds of the rosary pea or jequirity pea. Abrin, like ricin, is a ribosome inhibiting protein (RIP) and the toxin can also be found in the seeds of the castor oil plant.[3] It is classed as a "Select Agent" under U.S. law.