Rabbit liver microsomal 2-acetylamino- and 2-aminofluorene N-hydroxylase

Rabbit liver microsomes N-hydroxylate both 2-acetylaminofluorene (2-AAF) and 2-aminofluorene (2-AF). They also deacetylate N-hydroxy-2-acetylaminofluorene (N-OH-2-AAF). The enzymic activity towards the two substrates is the same but the enzyme has a higher affinity for the arylamide than for the arylamine. With regard to various modifiers added in vitro, rabbit liver microsomal N-hydroxylase behaves like those of rat, hamster and mouse. However, it is less effectively inhibited by the substituted imidazole derivative, Miconazole (MN). None of the enzymic properties of the rabbit liver microsomal N-hydroxylase investigated explains the resistance of this tissue to the carcinogenic effect of 2-AAF.