Differences in the kinetics of benzpyrene hydroxylation by hepatic drug-metabolizing enzymes from phenobarbital and 3-methylcholanthrene-treated rats

Ligand partitioning into membranes: Its significance in determining KM and KS values for cytochrome P‐450 and other membrane bound receptors and enzymes

“…When a first-order dissociation constant was assumed for this process a value of 1 PM was determined. This value is no higher than the determined values for benzpyrene hydroxylation [7,8]. This anomaly that the affinity of benzpyrene for the membrane is at least as high as that for the specific binding site of the enzyme, can be best explained if the enzyme active site is in the lipid environment.…”

Effect of 1.1.1 trifluoro-N-(2-methyl-4-phenyl sulfonyl) methane sulfonamide (Destun 50WP) on rat hepatic microsomal enzymes, aniline hydroxylase and amino-pyrine N-demethylase

“…It is universally accepted that 3-methylchloanthrene and phenobarbital, both well known inducers of microsomal mixed function oxidase system enzymes activities, act either by increasing the synthesis of the enzymes and thereby the rate of the reaction or by changing the affinity of the enzyme for the substrate (21)(22)(23)(24)(25)(26).…”

Mechanisms and consequences of the induction of microsomal enzymes of mammalian liver

“…In the induction of the hepatic microsomal mixedfunction oxidase system by 3-methylcholanthrene and other carcinogens, certain fundamental differences from phenobarbital induction have been observed in the nature of the terminal cytochrome and the mechanism of induction (Alvares et al, 1967(Alvares et al, , 1968Bresnick & Mosse, 1969). In the induction by safrole and other methylenedioxyaryl compounds, such as the insecticide synergist piperonyl butoxide, evidence for a new or modified cytochrome has been obtained that may result from the binding of a metabolite to cytochrome P450 (Parke & Rahman, 1971;Franklin, 1971).…”