Abstract The transport of citric cycle intermediates from cytosol to the mitochondrial matrix in rat liver mitochondria was studied in order to explain transport mechanism and molecular structure of the carriers. Anion, pH and cation influence on dicarboxylate, tricarboxylate and oxoglutarate carrier activities was examined kinetically and metal complexing agents like bathophenanthroline were used as an investigation tool for molecular structure of the carrier. The following conclusions were reached: 1. The substrates bind themselves on the mitochondrial membrane to a metal ion present in carrier molecules. 2. The primary effect of pH on the initial rate of uptake is due to a rise of ΔpH across the mitochondrial membrane. 3. Membrane surface, surrounded by the carrier environment, is negatively charged, and general cation stimulation of the rate of uptake is due to the positive electric charge which neutralizes amphoteric negatively charge groups of the membrane.