The binding of Bacillus natto isolated from natto to heterocyclic pyrolysates

The ability of natto, a fermented food, cells of bacterial strains isolated from natto,and viscous polymeric material (VPM) from natto to bind to pyrolysatesl such as Trp-P-1, Trp-P-2 and IQ (that are generated while cooking protein-enriched food and are potent mutagens) in the presence of an appropriate activation system was investigated. Strains of Bacillus natto bound 3-amino-1, 4-dimethyl-5H-pyrido(4,3-b)indole (Trp-P-1) and 3-amino-1-methyl-5H-pyrido(4,3- b)indole (Trp-P-2) effectively, bound 2-amino-3-methylinidazo(4,5f)quinoline (IQ) moderately, and bound 2-amino-6-methyl-dipyrido(1,2-a:3′2′-d) imidazole (Glu-P-1) weakly. The VPM bound to Trp-P-1 and Trp-P-2 strongly, but not to IQ. The cell wall fraction bound very strongly to Trp-P-2, whereas the cytoplasmic fraction lacked mutagen-binding activity. The binding of freeze-dried cells to Trp-P-2 was pH dependent, and influenced by metal ions. The strongest binding occurred at pH 7.0, while the inhibition effect increased with the concentration of metal ions. In addition, natto itself possessed the ability to bind with heterocyclic amino acid pyrolysates.