The metabolism of deoxyguanosine in mitochondria: relationship of the uptake of deoxyguanosine to the electron transport chain and adenosine triphosphate.

That deoxyguanosine is taken up by isolated rat liver mitochondria has been shown. This report describes the relationship between that uptake and oxidative phosphorylation. By measuring this process in the presence of standard inhibitors of oxidative phosphorylation it was determined that a functional electron transport chain, but not the phosphorylation of ADP, was essential for uptake. ATP analogs adenyl(beta,gamma-methylene)diphosphate and adenylimidodiphosphate blocked uptake, indicating that ATP hydrolysis was required. ADP also proved to be an inhibitor. Exogenous UTP slightly stimulated deoxyguanosine uptake, as did added ATP, but several other nucleotides (dGTP, dATP, UDP, dGDP) were inhibitory. A sulfhydryl group was important for deoxyguanosine uptake and inhibition of uptake by N-ethylmaleimide was protected by both deoxyguanosine and ATP. These data show that deoxyguanosine uptake by mitochondria is a process which is coordinated and, perhaps, regulated by other events which take place in the organelle.