RELATIVE REACTIVITIES OF AMINO-ACIDS IN PYRAZINE FORMATION

The contributions of N-15-labeled glycine and tested amino acids (glut amine, glutamic acid, asparagine, aspartic acid, lysine, arginine, phe nylalanine, and isoleucine) to pyrazine formation were investigated. A total of 56 pyrazines were identified in the present studies. Some sp ecific high molecular weight pyrazines were found in the reaction syst ems containing phenylalanine and isoleucine. In the presence of glycin e, glutamine and glutamic acid showed the least contributions, whereas asparagine had the highest contribution to pyrazine formation. By com paring the total yields of pyrazines generated from different reaction mixtures, it was found that the reaction mixture containing lysine ha d the highest, while the reaction mixture containing arginine possesse d the lowest. The results also implied that lysine was able to increas e the reactivity of glycine; however, arginine could decrease the capa bility of glycine to produce pyrazines. The variety and quantity of th e pyrazine formation depended on the reactivity and type of amino acid used.