Non-linear kinetics of microsomal styrene monooxygenase after phenobarbital pre-treatment

Pretreatment of rats with phenobarbital, but not with 3-methylcholanthrene, induces liver microsomal styrene monooxygenase. Under these conditions the kinetic profile is not linear and can be divided into 2 distinct curves. Evidence is presented indicating that the combined treatment with phenobarbital and CoCl2 destroy the affinity enzyme, suggesting that the native cytochrome is less sensitive to the action of CoCl2.