Effects of physical exercise and/or vitamin E on tissue oxidative metabolism.

arrangement of the redox components in the membrane as random rather than chain-like and they raise the question of the role of lateral diffusion in the mechanism of electron transport. We report here the rates of lateral diffusion for the major inner membrane redox components as determined by fluorescence recovery after photo-bleaching (Table 1, column I). Based on the diffusion coefficients established experimentally by our study, the theoretical diffusion-controlled electron-transport rate (Hardt, 1979), which is equal to the theoretical collision frequency (Table 1, column 2), is faster than the experimental maximum (uncoupled) electron-transport rate (Table 1, columns 3 and 4). Thus lateral diffusion of the redox components is sufficiently rapid for electron transport in the mitrochondrial inner membrane to be diffusion-controlled and is consistent with a 'random-collision model' (Hackenbrock, 1981) of electron transport in the mitochondrial inner membrane.