Reconstitution of the dicarboxylate exchange activity by incorporation into liposomes of a Triton-extract of mitochondrial rat-liver inner membranes.

The exchange between external [14C] malonate and internal malate or phosphate was reconstituted in liposomes prepared by incorporation of a Triton-extract of mitochondrial rat-liver inner membranes. The conditions of transport were investigated and the kinetic parameters of malonate-malate and malonate-phosphate exchanges were determined. The exchange was sensitive to butylmalonate and to organomercurials. Sulfate and phosphate decreased the rate of malonate-malate exchange and phosphate inhibition was found to be competitive. This report demonstrates the possibility to reconstitute a functional dicarboxylate transport and to use the system for further purification and for studies at the molecular level.