Mitochondrial coupling factors.

Abstract

Publisher Summary This chapter focuses on the mitochondrial coupling factors. Coupling factors are defined as being materials of mitochondrial origin that are essential for the process of energy conservation to function. The mitochondrial membrane loses its ability to synthesize ATP when the coupling factor is extracted from the membrane. This function can be restored when the coupling factor recombines with a membrane preparation specifically depleted of the coupling factor. Coupling factors are components of an uncharacterized multi-enzyme complex. Coupling factors with no known enzymatic activity are usually assayed by adding aliquots of solutions containing the coupling factor to suspensions of membranes deficient of an energy-linked function, for example, a complete or decreased ability to catalyze one or more of partial reactions of oxidative phosphorylation, ATPase, ATP-P i exchange, ATP-dependent reduction of NAD by succinate, and the energy-driven transhydrogenase reactions. The ability of the added coupling factor to stimulate or restore the chosen reaction catalyzed by the membranes is used as a measure of coupling factor activity