Some peculiarities of the steady-state kinetics of electron transfer in submitochondrial particles. A kinetic model based on the idea of activation on the respiratory chain induced by electron transfer

Abstract

1. The dependence of the steady-state levels of reduced cytochromes on the rate of electron transfer in submitochondrial particles has been studied. 2. The modified Pring equation (M. Pring, in F. Heinmets and L. D. Cady, Concepts and Models in Biomathematics, Dekker, New York, 1969, p. 75) has been used to calculate the rate constants for the interaction of adjacent cytochromes. The constants have been shown to increase linearily with increasing electron transfer rate in the steady state. 3. In order to explain these results a kinetic model has been suggested, based on the assumption that the respiratory chain exists in activated and non-activated forms the relationship of which depends on the rate of electron transfer. 4. The kinetic model gives an equation for the dependence of the steady-state levels of reduced cytochromes upon the rate of electron transfer. 5. The equation allows one to find the rate constants of interaction of the cytochromes (s −1) in the activated and non-activated respiratory chains. The values of the constants agree satisfactorily with the data of Pring and Chance obtained from non-stationary kinetics.