Mutagenicities of protein pyrolysates.

Smoke condensate obtained by pyrolysis of proteins, such as lysozyme and histone, was shown to be mutagenic to Salmonella typhimurium TA100 and TA98. In vitro metabolic activation by a mammaliam postmitochondrial enzyme preparation (S-9 Mix) was required. Smoke condensates obtained by pyrolysis of DNA, RNA, starch and vegetable oil were slightly mutagenic, whereas those from pyrolysis of L- and D-tryptophan and 5-hydroxy-D,L-tryptophan were very strongly mutagenic with metabolic activation by S-9 Mix. Because of the high correlation between mutagenicity and carcinogenicity, it is theorized that the cooking of proteinaceous foods might be an important cause of human cancers.