Presence of 3-amino-beta-carbolines (3-amino-9H-pyrido[3,4-b]indoles), effectors in the induction of sister-chromatid exchanges, in protein pyrolysates.

3-Amino-9H-pyrido[3,4-b]indole (3-aminonorharman) and 3-amino-1-methyl-9H-pyrido[3,4-b]indole (3-aminoharman), effectors for induction of sister-chromatid exchanges in human lymphoblastoid cells, were identified in pyrolysates of casein by high-performance liquid chromatography and UV spectrophotometry, together with some other mutagenic/carcinogenic carbolines. In pyrolysates from a preparation of zein, which contained little tryptophan, only norharman and harman were found in small amounts.