Increased participation of the outer mitochondrial membrane in the oxidation of exogenous NADH during aging of potato slices

Abstract

During aging of potato ( Solanum tuberosum L.) slices, the rate of oxidation of exogenous NADH by isolated mitochondria is increased by 50% on a protein basis. Experiments on isolated outer and inner mitochondrial membranes show that two NADH-dehydrogenases, one that is antimycin-sensitive and located on the outside of the inner mitochondrial membrane, and another that is antimycin-insensitive and located on the outer mitochondrial membrane, are involved in the increase in the rate of NADH oxidation. The inner membrane system accounts for the larger part of the total electron transfer from NADH. However, during aging, its activity increases less than 50%, whereas that of the outer membrane shows a sixfold increase.