Amino acids pyrolysis product mutagenicity

Table lV.B-4 lists several polynuclear (V-heterocyclic amines that exhibit extremely high mutagenicity levels in the Ames bioassay, are amino acid pyrolysis products, and have been identihed in various broiled, fried, or roasted foodstuffs as well as in CSC [Sugimura (3828c)]. On a per microgram basis, B[fl]P in the Ames bioassay with Salmonella typhimu-rium (Strain TA 98) shows about 200 revertants/pg. Several of the amino acid-derived compounds in Table lV.B-4 exceed the B[fl]P effect with the TA 98 strain by factors ranging from about 10 to over 2100. 

Methods were described for HPLC determination of the mutagenic and carcinogenic a-carbolines (56,57), y-carbolines (58,59)155 160, and other products of amino acid pyrolysis found in cigarette smoke, diesel exhaust and cooked foods and phenazines (60, 61) present as impurities of certain pesticides161. These compounds were also determined in human plasma, urine and bile161,162. 

Presently about 20 different mutagenic and/or carcinogenic heterocyclic amines (HAs) have been isolated from various heat-processed foods. One class of these HAs is formed by pyrolysis of proteins or some amino acids. These HAs are amino-carbolines (Figure 13.7), and have been identified in grilled, broiled, baked, and fried meat and fish products, in meat sauces and bouillons, as well as in pyrolyzed proteins, glutamate, lysine, phenylalanine, tryptophan, ornithine, and creatine. 

Dean, M. A., A. S. Dhaliwal, and W. R. Jones. Effects of Zingiberaceae rhizome extract of the infectivity of cyanophage LPP-1. Trans 111 State Acad Sci Suppl 1987 80 Abstr 83. Morita, K., M. Hara, and T. Kada. Studies on natural desmutagens screening for vegetable and fruits factors active in inactivation of mutagenic pyrolysis products from amino acids. Agr Biol Chem 1978 42(6) 1235-1238. 

Besides the determination of major pyrolysis products for amino acids, a special issue is the formation of several mutagenic compounds (heterocyclic amines) during pyrolysis. These types of compounds were detected in traces in the pyrolysates of amino acids, and the finding is very important as the amino acids are components of proteins and are present in food. Some of these compounds isolated from pyrolysates performed at 550 C from several amino acids [5,6] are shown below ... 

Nebert, D.W., S.W. Bigelow, A.B. Okey, T. Yahagi, Y. Mori, M. Nagao, and T. Sugimura Pyrolysis products from amino acids and proteins Highest mutagenicity requires cytochrome P1 50 Proc. Natl. Acad. Sci. U.S.A. 76 (1979) 5929-5933. 

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