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 malonatemalate 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.