The aflatoxins are agroup of closely related mycotoxins that are widely distributed in nature. The most important of the group is aflatoxin B1 (AFB1), which has a range ofbiological activities, including acute toxicity, teratogenicity, mutagenicityand carcinogenicity. In order for AFB1 to exert its effects, it must beconverted to its reactive epoxide by the action of the mixed functionmono-oxygenase enzyme systems (cytochrome P450-dependent) in the tissues (inparticular, the liver) of the affected animal. This epoxide is highlyreactive and can form derivatives with several cellular macromolecules,including DNA, RNA and protein. Cytochrome P450 enzymes may additionallycatalyse the hydroxylation (to AFQ1 and AFM1) and demethylation (to AFP1) ofthe parent AFB1 molecule, resulting in products less toxic than AFB1. Conjugation of AFB1 to glutathione (mediated by glutathione S-transferase)and its subsequent excretion is regarded as an important detoxificationpathway in animals. Suitable for use at 5ug/ml in immunoassays to identify aflatoxin B1. Dilute in PBS or medium which is identical to that used in the assay system. Each laboratory should determine an optimum working titer for use in its particular application. Other applications have not been tested but use in such assays should not necessarily be excluded.