The relation between structural and metabolic steady-states in isolated rat liver mitochondria. A study of the functional significance.

The possible functional significance of the close relation between structural and metabolic steady-states of isolated rat liver mitochondria, has been investigated by analysing the metabolic consequences of a primary block of the structural modifications. The structural changes have been blocked by means of factors acting primarily on the structure and the block was evaluated by electron microscope and angular light scattering measurements. Evidence has been obtained that: (a) the phosphorylative capacity of isolated mitochondria is not modified by conditions that completely abolish the structural changes; therefore, the configurational changes do not constitute as such a mechano-chemical mechanism for energy conservation and transformation. (b) The block of the structural changes is closely associated with the impairment of respiratory control: in fact there appears to be a close relation between the capacity of mitochondria to vary their structure and the ability to vary the respiratory rate, both being a function of ADP concentration.