Formation of a mutagen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine (PhIP) in cooked beef, by heating a mixture containing creatinine, phenylalanine and glucose.

When a mixture of creatinine, phenylalanine and glucose in diethylene glycol-water solution was heated for 2 h at 128 degrees C, a mutagen, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), was found to be produced, identified by high-performance liquid chromatography, and UV-visible and mass spectrometries. The yield of PhIP was 3.6 nmoles/mmole original creatinine. PhIP was originally isolated from cooked beef, and this study shows creatinine, phenylalanine and glucose to be the probable precursors of PhIP in beef.