Ricin is a highly toxic protein obtained from the pressed beans of which plant?
Ricin Ricin Ricin ( ), a lectin (a carbohydrate-binding protein) produced in the seeds of the castor oil plant, "Ricinus communis", is a highly potent toxin. A dose of purified ricin powder the size of a few grains of table salt can kill an adult human. The median lethal dose (LD) of ricin is around 22 micrograms per kilogram of body weight if the exposure is from injection or inhalation (1.78 milligrams for an average adult). Oral exposure to ricin is far less toxic as some of the poison is inactivated in the stomach. An estimated lethal oral dose in humans
Ricin is a globular, glycosylated heterodimer of approximately 60–65 kDa. Ricin toxin A chain and ricin toxin B chain are of similar molecular weights, approximately 32 kDa and 34 kDa, respectively. While other plants contain the protein chains found in ricin, both protein chains must be present in order to produce toxic effects. For example, plants that contain only protein chain A, such as barley, are not toxic because without the link to protein chain B, protein chain A cannot enter the cell and do damage to ribosomes. Ricin B chain binds complex carbohydrates on the surface of eukaryotic cells containing