Energization of mitochondrial inner membranes by L-malate under anaerobic condition is driven by energy derived at side I of phosphorylation.

Abstract

It was shown that addition of L-malate to anaerobic mitochondria, like addition of adenosine triphosphate, caused a red shift of the absorbance maximum, and an increase in the fluorescence of ethidium. These responses of ethidium were sensitive to uncouplers and roteone. They were not inhibited by antimycin A, KCN or oligomycin.These results show that addition of L-malate to anaerobic, KCN-or antimycin A-inhibited mitochondria caused energization of the mitochondrial inner membranes. Furthermore, this energization of the membranes was reversed by succinate, malonate, and theoyltrifluoroacetone. Thus, the present results clearly show that L-malate-induced energization of anaerobic mitochondria was driven by energy derived from redox reactions at site I of phosphorylation.