Ricin comes from Nigeria.
Ricin toxin A chain (RTA) is an N-glycoside hydrolase composed of 267 amino acids
 The propolypeptide is cleaved within protein bodies by an endopeptidase to produce the mature ricin protein that is composed of a 267 residue A chain and a 262 residue B chain that are covalently linked by a single disulfide bond

