RELATIVE REACTIVITIES OF AMINO-ACIDS IN PYRAZINE FORMATION

The contributions of N-15-labeled glycine and tested amino acids (glutamine, glutamic acid, asparagine, aspartic acid, lysine, arginine, phenylalanine, and isoleucine) to pyrazine formation were investigated. A total of 56 pyrazines were identified in the present studies. Some specific high molecular weight pyrazines were found in the reaction systems containing phenylalanine and isoleucine. In the presence of glycine, glutamine and glutamic acid showed the least contributions, whereas asparagine had the highest contribution to pyrazine formation. By comparing the total yields of pyrazines generated from different reaction mixtures, it was found that the reaction mixture containing lysine had the highest, while the reaction mixture containing arginine possessed the lowest. The results also implied that lysine was able to increase the reactivity of glycine; however, arginine could decrease the capability of glycine to produce pyrazines. The variety and quantity of the pyrazine formation depended on the reactivity and type of amino acid used.