Metabolite transport in isolated yeast mitochondria: fumarate/malate and succinate/malate antiports

In this study, we investigated the metabolite permeability of isolated coup led Saccharomyces cerevisiae mitochondria, The occurrence of a fumarate/mal ate antiporter activity was shown. The activity differs from that of the di carboxylate carrier (which catalyses the succinate/malate antiport) in (a) kinetics (K-m, and V-max,,, values are about 27 mu M and 22 nmol min(-1) mg protein(-1) and 70 mu M and 4 nmol min(-1) mg protein(-1) respectively), ( b) sensitivity to inhibitors, (c) Ki for the competitive inhibitor phenylsu ccinate and (d) pH profiles. (C) 1999 Federation of European Biochemical So cieties.