MeIQx (MeIQx) is a food-derived carcinogen that has been found in high temperature-cooked fish and meats.1It is activated by hydroxylation and subsequent O-acetylationviathe cytochrome P450 (CYP) isoform CYP1A2 and N-acetyltransferase 2, respectively, in UV5 cells expressing the human enzymes to a metabolite that reacts with DNA to form adducts.2MeIQx (200 and 400 ppm in the diet) induces tumor formation in rats.3
N-Nitroso sarcosine is a carcinogen and nitrosation product of sarcosine that has been found in cured meat products.1,2In vivo, N-nitroso sarcosine (225 mg kg) induces the formation of metastatic liver carcinomas in mice.2 1.Janzowski, C., Eisenbrand, G., and Preussmann, R.Occurrence of N-nitrosamino acids in cured meat products and their efffect on formation of N-nitrosamines during heatingFood Cosmet. Toxicol.16(4)343-348(1978) 2.Wogan, G.N., Paglialunga, S., Archer, M.C., et al.Carcinogenicity of nitrosation products of ephedrine, sarcosine, folic acid, and creatinineCancer Res.35(8)1981-1984(1975)
N-Nitroso-N-methyl-4-aminobutyric acid (NMBA) is a tobacco-specific nitrosamine carcinogen.1It is oxidized to the reactive metabolite methyl-2-oxopropylnitrosamine (MOPN) in isolated rat liver mitochondria.2NMBA induces bladder transitional cell carcinomas in rats when administered in the drinking water at a concentration of 300 mg L per day.3