Cooked-Meat Derived Aromatic Amine Mutagens and Their Immunoassay
Typical household cooking of meat produces a family of aromatic amine mutagens termed aminoimizodazaarenes (AIAs). This family contains among other members PhIP(2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine), IQ (2-amino-3methylimidazo[4,5-f]quinoline), and MelQx (2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline). Along with the nitro-aromatics, these are some of the most mutagenic compounds ever tested in bacterial mutagenesis assays. Where tested, the AIAs are also carcinogens. Typical levels of AIAs in well-done cooked beef are 0.1, 1.0, and 10 ppb for IQ, MeIOx, and PhIP, respectively. This low level of presence in foods hampers analysis of AIAs in the diet. To facilitate AIA assay we have developed a set of monoclonal antibodies to the AIAs. Individual antibodies have been selected that react with IQ, MeIOx and PhIP. These antibodies are being used to quantify the levels of individual AIAs in various cooked meats. In addition, analysis of well-done beef shows the presence of other, currently unknown, structurally related compounds that immunochemically cross-react with the antibodies. The antibodies also recognize compounds present in the urine of people on diets of well-done beef, but not people eating vegetarian diets. These findings suggest that the antibodies may be useful as biochemical markers of human exposure to dietary meat mutagens. The antibodies also may provide a means of concentrating and purifying human metabolites of AIAs from urine.