Formation of mutagens by amino-carbonyl reactions

The formation of mutagens by amino-carbonyl reactions of 20 kinds of amino acid and sugars after heating at 100 degrees C for 10 h was examined by the Ames test. The browned solutions of Gly, Ala, Val, Leu, Ile, Ser, Thr, Gln, Lys X HCl, Arg, Phe, Cys, Met and Pro with Glc caused mutation of Salmonella typhimurium TA100 and/or TA98 with or without S9 mix. The presence of S9 mix increased the mutagenic activity of the browned solutions of Cys and Phe with Glc on TA100 and of those of Gly, Ala, Val, Ile and Cys on TA98, but decreased the activity of other solutions. No revertants of Salmonella were induced by the browned solutions of Trp, Tyr, Asp, Asn, Glu and (Cys)2 with Glc. Among positive browned solutions, Cys, Lys, Arg and Phe had the stronger activity, but their activity was weak compared with that of pyrolysates or chemical mutagens such as Trp-P-1, Trp-P-2 and 4-nitroquinoline-N-oxide. The mutagenic activity of the browned solutions increased with prolongation of heating time and varied with the pH of the reaction mixture. Fru, Gal, Ara, Xyl, Man, Lac and Suc also had the ability to form mutagens in the browning reactions with amino acids.