Abstract
Hydroxylation of 2-(2-amino-5-bromobenzoyl) pyridine (ABBP) to 3-OH-ABBP in animal liver was found to be mediated by the microsomal mixed-function oxidase system requiring nicotinamide adenine dinucleotide phosphate reduced form (NADPH) and O2. When ABBP was incubated with microsomal fraction prepared from the liver of rats treated with phenobarbital or benzo [α] pyrene, hydroxylation of ABBP was enhanced about 2-fold of that of control rats. Hydroxylation of ABBP by microsomes of rats and rabbits was inhibited by SKF-525A, HgCl2, CuCl2, p-chloromercuribenzoate (PCMB), cytochrome c, and CO. The kinetic constants of ABBP hydroxylation by liver microsomes of various animal species indicated a similar affinity of ABBP. It is of interest that a factor which activates the hydroxylating activity was found in the soluble fraction of various organs of animals.
