Binding of dimethylaminoazobenzene metabolites to DNA and proteins. I. In vitor studies on a microsomal dependent system

Incubating dimethylaminoazobenzene [aniline ring (U)¹⁴ C] (DAB), purified thymus DNA and rat liver microsomes led to a covalent binding of radioactivity to DNA and proteins, which implied the presence of bound DAB metabolites. This binding required an enzymatic activation. We studied some characteristics of the enzymatic process, i.e. NADPH requirement, effect of pH, effect of various concentrations of microsomes and DNA, induction by 3-methylcholanthrene. This in vitro system is discussed in view of its validity for studying interactions between the carcinogenic azodyes and the cellular constituents.