Kinetics of N-dealkylation of amines with participation of microsomal cytochrome P-450

Within the temperature range of 20-37 degrees C the kinetics of the demethylation reactions of a variety of amines with participation of hepatic microsomal cytochrome P-450, NADPH and O2 has been studied. Catalytical rate constants for all the substrates have been determined in generalized forms. Activation parameters deltaH* and deltaS* are also estimated. There is a linear relationship between deltaH* and deltaS*: deltaH*=20.7 kcal+366 degrees K deltaS*. Compensation relationship is characterized by a coefficient alpha=366 degrees/Taverage=1.21. The nature of the limiting step of the enzymatic amine demethylation involving cytochrome P-450 of hepatic microsomes is discussed.