10-05-2014, 07:17 AM
The natural toxin ricin is isolated from endosperm of castor. It consists of two polypeptide chains called as A and B where the polypeptide A accounts for its toxicity. The immunotoxin formed as a conjugate between an antibody and ricin A chain results in specific binding to tumour cells and irreversible enzymatic modification of ribosomes preventing protein synthesis is such cells.