Modulation of the electrochemical membrane potential in mitochondria by sulfhydryl reagents

Abstract

It has been found that both N-ethylmaleimide and mersalyl promote the dissipation of the mitochondrial membrane potential generated by the respiratory chain activity. Although the two sulfhydryl reagents have differential effects which can be ascribed to the differential accessibility of SH groups blocked by them, the results obtained indicate that thiol groups are involved in the generation and conservation of membrane potential. Evidence has been obtained showing that the N-ethylmaleimide effect cannot be ascribed to the inhibition of primary dehydrogenases. The possibility that N-ethylmaleimide may promote an additional electron withdrawal from the NADH-cytochrome c region of the respiratory chain, has been considered.