Ricin is a globular protein that makes up 1% to 5% by weight of the bean of the castor plant. Ricin can be found in all parts of the castor bean plant, but is most concentrated in the beans and in the mash that remains after processing for castor oil.
Ricin causes toxicity by inhibiting the formation of proteins in cells causing cell death. The toxin consists of two chains (A and B) that are linked by a disulfide bond. Each chain must be present to cause toxicity. Lethal toxicity can vary 100 fold per kilogram of bodyweight between species.
The N.C. State Laboratory of Public Health can test for ricin if a credible threat is present. The NCSLPH recommends that all agencies should follow proper law enforcement channels and contact the NCSLPH for notification of sample delivery.