Biotransformation of the carcinogen chrysazin by NADPH-microsome system

The interactions of chrysazin, a carcinogenic anthraquinone, with electron transport systems in microsomes and mitochondria (submitochondrial particles, SMP) were studied. The NADPH-dependent oxygen uptake in microsomes was significantly enhanced by chrysazin and no such effect was observed in the NADH-dependent reactions in microsomes and SMP. The NADPH-microsome system caused a marked alteration in the visible absorption spectrum of chrysazin. These results strongly suggest that chrysazin is biotransformed selectively by the NADPH-microsome system.