Stochastic ESR analysis of rat liver and hepatoma mitochondrial lipids.

A commonly used model for the interaction of the motional narrowing of ESR lines is shown to be qualitatively misleading. An analysis of lipid extracts of mitochondrial preparations labeled with 12-nitroxide stearic acid produced linear plots of the logarithm of the correlation time versus the reciprocal of the absolute temperature when analyzed with stochastic computer simulations. However, when the data were analyzed with isotropic Lorentzian line shape approximations, nonlinear plots were obtained.